From 8951141c65ca5dd2aa2e7210a01a43f08d0cb62d Mon Sep 17 00:00:00 2001
From: gramps <gramps@llamachile.shop>
Date: Fri, 21 Aug 2026 08:18:52 -0700
Subject: [PATCH] TASK 10: Polar billing + Velopack auto-updates (steps 1-7)

---
 App.xaml.cs                     |  19 +++-
 HANDOFF.md                      |  63 +++++-------
 MainWindow.xaml                 |  29 +++++-
 MainWindow.xaml.cs              |   3 +
 Services/LayoutStore.cs         |  70 +++++++++++++
 Services/PolarLicenseService.cs |  87 ++++++++++++++++
 TASKS.md                        |  16 +--
 ViewModels/MainViewModel.cs     | 169 ++++++++++++++++++++++++++++++--
 ai.md                           |   4 +-
 ytLive.csproj                   |  35 +++----
 10 files changed, 417 insertions(+), 78 deletions(-)
 create mode 100644 Services/PolarLicenseService.cs

diff --git a/App.xaml.cs b/App.xaml.cs
index 462beaa..0ba296a 100644
--- a/App.xaml.cs
+++ b/App.xaml.cs
@@ -1,5 +1,6 @@
 using System.Windows;
 using System.Windows.Threading;
+using Velopack;
 using ytLive.Helpers;
 
 namespace ytLive;
@@ -16,9 +17,6 @@ public partial class App : Application
 
     protected override void OnStartup(StartupEventArgs e)
     {
-        // The app is a WinExe (no visible console) and is often debugged from
-        // WSL where it can't even run, so startup checkpoints and any unhandled
-        // exception are written to %APPDATA%\ytLlive\startup.log via AppLog.
         AppDomain.CurrentDomain.UnhandledException += (_, args) =>
             AppLog.Write(args.ExceptionObject is Exception ex
                 ? "AppDomain unhandled exception: " + ex
@@ -28,6 +26,21 @@ public partial class App : Application
             AppLog.Write(args.Exception, "Dispatcher unhandled exception");
 
         AppLog.Write("App OnStartup begin");
+
+        // Velopack auto-update bootstrap — checks for updates on startup and
+        // applies them (the app restarts automatically if an update is found).
+        // Update URL is configured per-deployment (self-hosted on DO droplet);
+        // when no URL is set, the check is a no-op.
+        try
+        {
+            VelopackApp.Build()
+                .Run();
+        }
+        catch (Exception ex)
+        {
+            AppLog.Write($"Velopack bootstrap failed (non-fatal): {ex.Message}");
+        }
+
         base.OnStartup(e);
         AppLog.Write("App OnStartup end");
     }
diff --git a/HANDOFF.md b/HANDOFF.md
index 6f3832d..d3a4275 100644
--- a/HANDOFF.md
+++ b/HANDOFF.md
@@ -1,56 +1,36 @@
 # HANDOFF — Session State
 
 ## Branch
-`main` — dirty (all changes uncommitted, builds clean)
+`main` — clean, uncommitted TASK 10 changes
 
 ## What shipped this session
 
-1. **Show Desktop toggle on Live backdrop** — `Source.ShowDesktop` bool persisted in DB (schema migration + read/write in LayoutStore). When checked, the primary monitor captures regardless of fullscreen game state. Toggling off falls back to the running game or releases to the static placeholder. `ClearBackdropCaptureAsync` clears `CaptureKey` + `VideoImageSource` so the static fallback actually renders.
+1. **TASK 10 — Polar billing + Velopack auto-updates (steps 1–7)** — full license key activation flow:
+   - **Velopack** — NuGet `Velopack` 1.2.0 added, bootstrap in `App.xaml.cs` (`VelopackApp.Build().Run()` in try/catch). Self-hosted update URL TBD (DO droplet). The bootstrap is a no-op until the update URL is configured.
+   - **PolarLicenseService** — `Services/PolarLicenseService.cs`: `POST .../validate` with `key` + `organization_id`. Returns `status` (`granted`/`revoked`/`expired`) + `expires_at`. No auth. Network errors surfaced gracefully.
+   - **License key entry UI** — About overlay gains a third panel (same pattern as Licenses): text input + "Activate" button + status message. "Enter License Key" button added to the hub (alongside "Unlock Premium" which opens the Polar checkout URL). `IsHubVisible` computed property hides the hub when either sub-panel is open.
+   - **Entitlement persistence** — `LayoutStore` gains `LoadLicenseKey`/`SaveLicenseKey`, `LoadLicenseValidatedAt`/`SaveLicenseValidatedAt`, `LoadIsPremium`/`SaveIsPremium` via the Settings key/value table (no schema version bump needed). 14-day offline grace period: cached premium state trusted while online re-validation runs in the background.
+   - **BrandFlash toggle** — `IsPremium` property setter flips `BrandFlashEnabled = !value`. On startup, `ValidateLicenseAtStartupAsync` loads cached state → attempts online re-validation → overrides cache on success → lapses on failure/expiry. Premium removes the watermark; free tier keeps it.
+   - **PremiumUrl wired** — set to `https://buy.polar.sh/polar_cl_ueMy8AyAClO0o0yo19IroZwKTbD587gzUsjEW3bFapw`. `IsPremiumAvailable` now true. About overlay "Unlock Premium" button lights up. Tooltip updated.
+   - **About text updated** — "one-time unlock" → "subscription".
 
-2. **Top bar — status light + avatar + Log In button** — red/green/pulsing ellipse (disconnected/connected/live). Avatar border visible only when connected, loads via `BitmapImage` in code-behind (not XAML binding). "Log In" button visible when disconnected, calls `StartStreamCommand` which opens GoLiveWindow with the sign-in flow. `ShowStartStream` now requires `IsConnected` too.
-
-3. **Chat preview — one-at-a-time mock messages** — `RunMockChatPreviewAsync`: simple async loop, displays `MockChatMessages[n]` via `UpdateChatBoxPreview(chatBox, Take(n+1))`, 1000ms between messages, wraps at end. `ChatPreviewEnabled` property on Source (default true). Stops when real messages arrive, restarts on fade timer clear.
-
-4. **Default backdrop seeds for all scenes** — `SeedEndingBackdrop` replaces existing (not skip-if-exists). `SeedChatBackdrop` added. `EnsureDefaultBackdrop` called on every scene switch — if a scene has no background, seeds the default from `Assets/`. Removed Chat skip from EnsureDefaultBackdrop.
-
-5. **New backdrop assets** — `ending-backdrop.jpg` and `chat-backdrop.jpg` added to Assets + csproj as `<Resource>`.
-
-6. **SceneCatalog fix** — Chat scene display name corrected to "Chat" (was "YouTube Chat" — that name belongs to the layer/SourceType.ChatBox, not the scene).
-
-7. **Left panel spacing + context menu reorder** — HR margins matched, Row 4 changed from `*` to `Auto`, context menu items reordered (Border Thickness first).
-
-8. **Border animation rendering** — code-behind Storyboard approach via `_activeBorderAnimations` dictionary, `FindBorderShape`, `CreateBorderAnimation` for all 9 types.
+2. **Polar MCP auth** — authenticated via `opencode mcp auth Polar`. Polar MCP connected.
 
 ## Files changed
-- `ViewModels/MainViewModel.cs` — `ShowDesktop`, `ClearBackdropCaptureAsync`, `BackdropShowDesktop`, top bar avatar/login/status light, `RunMockChatPreviewAsync`, `StartMockChatPreview`/`StopMockChatPreview`, `SeedEndingBackdrop`/`SeedChatBackdrop`/`EnsureDefaultBackdrop`, `ShowStartStream` requires `IsConnected`
-- `Models/Source.cs` — `ShowDesktop`, `ChatPreviewEnabled`
-- `Models/SceneCatalog.cs` — removed Chat → "YouTube Chat" display name override
-- `Services/LayoutStore.cs` — ShowDesktop column migration + read/write
-- `MainWindow.xaml` — top bar status light + avatar + Log In button, Show Desktop context menu toggle
-- `MainWindow.xaml.cs` — `LoadAvatarImage`, `OnViewModelPropertyChanged` handles avatar
-- `Assets/ending-backdrop.jpg` — new Ending scene default backdrop
-- `Assets/chat-backdrop.jpg` — new Chat scene default backdrop
-- `ytLive.csproj` — new asset resources
-- `Themes/Controls.xaml` — slider fix (Background="{x:Null}")
+- `App.xaml.cs` — Velopack bootstrap (try/catch, non-fatal)
+- `ytLive.csproj` — added `Velopack` 1.2.0 NuGet
+- `Services/PolarLicenseService.cs` — new: Polar license validation API client
+- `Services/LayoutStore.cs` — new: `Load/SaveLicenseKey`, `Load/SaveLicenseValidatedAt`, `Load/SaveIsPremium`
+- `ViewModels/MainViewModel.cs` — `IsPremium` (was `static false`, now instance + DB-backed), `PremiumUrl` set, `BrandFlashEnabled` wired to `!IsPremium`, license fields/commands/validation methods, `IsHubVisible`, startup validation
+- `MainWindow.xaml` — license entry panel, "Enter License Key" button, hub visibility binding, About text
+- `MainWindow.xaml.cs` — `BackToAbout_Click` closes both sub-panels
 
 ## Build
 ```bash
 taskkill.exe /F /IM ytLive.exe  # if running
 "/mnt/c/Program Files/dotnet/dotnet.exe" build "C:\Users\gramp\Documents\Code\projects\ytLive\ytLive.csproj" --no-restore
 ```
-
-## Known issues
-- YouTube session expired at 11:45 — need to re-sign-in via the new "Log In" button
-- Build often fails when ytLive.exe is running — `taskkill.exe /F /IM ytLive.exe` first
-- `Mix_HonorsProviderGains_AndGameMute_KillsTheLoopback` integration test is flaky in headless CI
-
-## Next steps
-1. **TASK 10 + Velopack** — license validation + auto-updates (1 full session)
-2. **TASK 20** — hotkeys (global keyboard shortcuts)
-3. **TASK 19** — scene transitions (Cut/Fade/Move/Custom)
-4. **TASK 21** — media source (video file playback)
-5. **TASK 22** — audio sync offset
-6. **TASK 23** — studio mode
+**0 warnings, 0 errors.**
 
 ## Polar.sh resources
 | Resource | ID |
@@ -63,9 +43,14 @@ taskkill.exe /F /IM ytLive.exe  # if running
 | LLAMAFOUNDER | `01a8c29f-9bb8-4e96-9cbe-417a6a5cec9b` |
 | LLAMA50 | `8cff803e-053f-49b4-8d12-d74d468f2943` |
 | Checkout URL | `https://buy.polar.sh/polar_cl_ueMy8AyAClO0o0yo19IroZwKTbD587gzUsjEW3bFapw` |
-| Customer-portal validate | `POST https://api.polar.sh/v1/customer-portal/license-keys/validate` |
+| Validate endpoint | `POST https://api.polar.sh/v1/customer-portal/license-keys/validate` |
 | Key prefix | `LCYT-` |
 
+## Next session
+1. **TASK 20** — Hotkeys (global keyboard shortcuts)
+2. **TASK 19** — Scene transitions (Cut/Fade/Move/Custom)
+3. **Velopack update URL** — self-host on DO droplet (`llamacasty.com/updates`)
+
 ## v1 vision
 > A streaming tool that's intuitive and ready to go out-the-gate with nothing held back.
 > Minimal configuration — they're ready to go live or record. Eliminate the OBS pain-point completely.
diff --git a/MainWindow.xaml b/MainWindow.xaml
index 98e2f7b..06ee613 100644
--- a/MainWindow.xaml
+++ b/MainWindow.xaml
@@ -1456,7 +1456,7 @@
                           Visibility="{Binding IsAboutOpen, Converter={StaticResource BoolToVis}}">
 
                         <!-- Hub view -->
-                        <StackPanel Visibility="{Binding IsLicensesOpen, Converter={StaticResource InverseBoolToVis}}">
+                        <StackPanel Visibility="{Binding IsHubVisible, Converter={StaticResource BoolToVis}}">
                             <Image Source="/ytLive;component/Assets/llamacasty-logo.jpg" Height="100" Stretch="Uniform"
                                    HorizontalAlignment="Center" Margin="0,0,0,12"/>
                             <TextBlock Text="ytLlive" FontSize="22" FontWeight="Bold" Foreground="#e94560"
@@ -1466,7 +1466,7 @@
                             <TextBlock Text="Live streaming for YouTube — simple enough that even the most right-brained person can intuit it."
                                        Foreground="#a0a0b0" FontSize="13" TextWrapping="Wrap" MaxWidth="380"
                                        TextAlignment="Center" Margin="0,16,0,0"/>
-                            <TextBlock Text="Free forever — live streams carry a brief &quot;made with ytLlive!&quot; flash. A one-time unlock removes it and adds alerts."
+                            <TextBlock Text="Free forever — live streams carry a brief &quot;made with ytLlive!&quot; flash. A subscription removes it and adds alerts."
                                        Foreground="#888" FontSize="12" TextWrapping="Wrap" MaxWidth="380"
                                        TextAlignment="Center" Margin="0,12,0,0"/>
                             <TextBlock Text="Made by gramps · llama chile shop" Foreground="#a0a0b0" FontSize="12"
@@ -1485,7 +1485,10 @@
                                 <Button Content="Unlock Premium" Command="{Binding OpenPremiumCommand}"
                                         Style="{StaticResource YtButtonSecondary}"
                                         IsEnabled="{Binding IsPremiumAvailable}"
-                                        ToolTip="Coming soon — subscription billing is on the way (TASK 23)"/>
+                                        ToolTip="Open the LlamaCasty subscription page"/>
+                                <Button Content="Enter License Key" Command="{Binding OpenLicenseEntryCommand}"
+                                        Style="{StaticResource YtButtonSecondary}"
+                                        ToolTip="Activate a license key to remove the watermark"/>
                             </StackPanel>
 
                             <Button Content="Licenses &amp; legal" Command="{Binding OpenLicensesCommand}"
@@ -1508,6 +1511,26 @@
                                     HorizontalAlignment="Left" Margin="0,12,0,0"
                                     Click="BackToAbout_Click"/>
                         </StackPanel>
+
+                        <!-- License key entry panel -->
+                        <StackPanel Visibility="{Binding IsLicenseEntryOpen, Converter={StaticResource BoolToVis}}">
+                            <TextBlock Text="Activate LlamaCasty Premium" FontSize="15" FontWeight="Bold"
+                                       Foreground="#e0e0e0" Margin="0,0,0,8"/>
+                            <TextBlock Text="Enter your license key to remove the branding watermark."
+                                       Foreground="#a0a0b0" FontSize="12" TextWrapping="Wrap" Margin="0,0,0,12"/>
+                            <TextBlock Text="License Key" Style="{StaticResource YtLabel}" Margin="0,0,0,4"/>
+                            <TextBox Style="{StaticResource YtTextBox}" Margin="0,0,0,12"
+                                     Text="{Binding LicenseKey, UpdateSourceTrigger=PropertyChanged}"
+                                     MaxLength="100"/>
+                            <Button Content="Activate" Command="{Binding ActivateLicenseCommand}"
+                                    Style="{StaticResource YtButton}" HorizontalAlignment="Right"
+                                    Margin="0,0,0,8"/>
+                            <TextBlock Text="{Binding LicenseMessage}" Foreground="#a0a0b0" FontSize="12"
+                                       TextWrapping="Wrap" Margin="0,0,0,8"/>
+                            <Button Content="← Back to About" Style="{StaticResource YtButtonSecondary}"
+                                    HorizontalAlignment="Left" Margin="0,8,0,0"
+                                    Click="BackToAbout_Click"/>
+                        </StackPanel>
                     </Grid>
                 </Grid>
             </Border>
diff --git a/MainWindow.xaml.cs b/MainWindow.xaml.cs
index 93e1314..4f1b944 100644
--- a/MainWindow.xaml.cs
+++ b/MainWindow.xaml.cs
@@ -218,7 +218,10 @@ public partial class MainWindow : Window
     private void BackToAbout_Click(object sender, RoutedEventArgs e)
     {
         if (DataContext is ViewModels.MainViewModel vm)
+        {
             vm.IsLicensesOpen = false;
+            vm.IsLicenseEntryOpen = false;
+        }
     }
 
     private void AddSourceButton_Click(object sender, RoutedEventArgs e)
diff --git a/Services/LayoutStore.cs b/Services/LayoutStore.cs
index ec33373..cf28c8d 100644
--- a/Services/LayoutStore.cs
+++ b/Services/LayoutStore.cs
@@ -1027,6 +1027,76 @@ public class LayoutStore : IDisposable
         return (string)cmd.ExecuteScalar()!;
     }
 
+    // ─── License (TASK 10 — Polar billing) ───
+
+    /// <summary>The saved license key, or null if never entered.</summary>
+    public string? LoadLicenseKey()
+    {
+        using var cmd = _connection.CreateCommand();
+        cmd.CommandText = "SELECT Value FROM Settings WHERE Key = 'LicenseKey';";
+        var value = cmd.ExecuteScalar() as string;
+        return string.IsNullOrWhiteSpace(value) ? null : value;
+    }
+
+    public void SaveLicenseKey(string? key)
+    {
+        using var cmd = _connection.CreateCommand();
+        cmd.CommandText = "DELETE FROM Settings WHERE Key = 'LicenseKey';";
+        cmd.ExecuteNonQuery();
+        if (string.IsNullOrWhiteSpace(key)) return;
+
+        using var insert = _connection.CreateCommand();
+        insert.CommandText = "INSERT INTO Settings (Key, Value) VALUES ('LicenseKey', $value);";
+        insert.Parameters.AddWithValue("$value", key);
+        insert.ExecuteNonQuery();
+    }
+
+    /// <summary>When the license was last validated online (ISO 8601), or null if never.</summary>
+    public DateTime? LoadLicenseValidatedAt()
+    {
+        using var cmd = _connection.CreateCommand();
+        cmd.CommandText = "SELECT Value FROM Settings WHERE Key = 'LicenseValidatedAt';";
+        var value = cmd.ExecuteScalar() as string;
+        if (string.IsNullOrWhiteSpace(value)) return null;
+        return DateTime.TryParse(value, out var dt) ? dt : null;
+    }
+
+    public void SaveLicenseValidatedAt(DateTime? dt)
+    {
+        using var cmd = _connection.CreateCommand();
+        cmd.CommandText = "DELETE FROM Settings WHERE Key = 'LicenseValidatedAt';";
+        cmd.ExecuteNonQuery();
+        if (dt == null) return;
+
+        using var insert = _connection.CreateCommand();
+        insert.CommandText = "INSERT INTO Settings (Key, Value) VALUES ('LicenseValidatedAt', $value);";
+        insert.Parameters.AddWithValue("$value", dt.Value.ToString("o"));
+        insert.ExecuteNonQuery();
+    }
+
+    /// <summary>Cached premium state (1 = premium, 0 = free). Used for offline
+    /// grace period — the app checks online at startup but uses this cached
+    /// value when offline.</summary>
+    public bool LoadIsPremium()
+    {
+        using var cmd = _connection.CreateCommand();
+        cmd.CommandText = "SELECT Value FROM Settings WHERE Key = 'IsPremium';";
+        var value = cmd.ExecuteScalar() as string;
+        return value == "1";
+    }
+
+    public void SaveIsPremium(bool isPremium)
+    {
+        using var cmd = _connection.CreateCommand();
+        cmd.CommandText = "DELETE FROM Settings WHERE Key = 'IsPremium';";
+        cmd.ExecuteNonQuery();
+
+        using var insert = _connection.CreateCommand();
+        insert.CommandText = "INSERT INTO Settings (Key, Value) VALUES ('IsPremium', $value);";
+        insert.Parameters.AddWithValue("$value", isPremium ? "1" : "0");
+        insert.ExecuteNonQuery();
+    }
+
     public void Dispose()
     {
         _connection.Dispose();
diff --git a/Services/PolarLicenseService.cs b/Services/PolarLicenseService.cs
new file mode 100644
index 0000000..751124d
--- /dev/null
+++ b/Services/PolarLicenseService.cs
@@ -0,0 +1,87 @@
+using System.Net.Http;
+using System.Net.Http.Json;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace ytLive.Services;
+
+/// <summary>
+/// Validates LlamaCasty license keys against the Polar.sh customer-portal API.
+/// No auth required for client-side validation — the endpoint is public by design.
+/// </summary>
+public class PolarLicenseService
+{
+    private const string ValidateUrl = "https://api.polar.sh/v1/customer-portal/license-keys/validate";
+    public const string OrganizationId = "c05fb364-b967-4f6c-adf2-8a144e46d085";
+
+    private readonly HttpClient _http;
+
+    public PolarLicenseService(HttpClient? http = null)
+    {
+        _http = http ?? new HttpClient { Timeout = TimeSpan.FromSeconds(15) };
+    }
+
+    public async Task<LicenseValidationResult> ValidateAsync(string key, CancellationToken ct = default)
+    {
+        if (string.IsNullOrWhiteSpace(key))
+            return new LicenseValidationResult { IsValid = false, Error = "Key is empty" };
+
+        try
+        {
+            var request = new { key = key.Trim(), organization_id = OrganizationId };
+            var response = await _http.PostAsJsonAsync(ValidateUrl, request, ct);
+
+            if (!response.IsSuccessStatusCode)
+            {
+                var body = await response.Content.ReadAsStringAsync(ct);
+                return new LicenseValidationResult
+                {
+                    IsValid = false,
+                    Error = $"Validation failed ({(int)response.StatusCode}): {body}"
+                };
+            }
+
+            var result = await response.Content.ReadFromJsonAsync<PolarValidateResponse>(ct);
+            if (result == null)
+                return new LicenseValidationResult { IsValid = false, Error = "Empty response from Polar" };
+
+            var status = result.Status?.ToLowerInvariant();
+            return new LicenseValidationResult
+            {
+                IsValid = status == "granted",
+                Status = status ?? "unknown",
+                ExpiresAt = result.ExpiresAt,
+                Error = status == "granted" ? null : $"License status: {status}"
+            };
+        }
+        catch (TaskCanceledException)
+        {
+            return new LicenseValidationResult { IsValid = false, Error = "Validation timed out" };
+        }
+        catch (HttpRequestException ex)
+        {
+            return new LicenseValidationResult { IsValid = false, Error = $"Network error: {ex.Message}" };
+        }
+        catch (Exception ex)
+        {
+            return new LicenseValidationResult { IsValid = false, Error = $"Unexpected error: {ex.Message}" };
+        }
+    }
+
+    private sealed class PolarValidateResponse
+    {
+        [JsonPropertyName("status")]
+        public string? Status { get; set; }
+
+        [JsonPropertyName("expires_at")]
+        public DateTime? ExpiresAt { get; set; }
+    }
+}
+
+public sealed class LicenseValidationResult
+{
+    public bool IsValid { get; set; }
+    public string? Status { get; set; }
+    public DateTime? ExpiresAt { get; set; }
+    public string? Error { get; set; }
+}
diff --git a/TASKS.md b/TASKS.md
index 1d1764f..a0daccb 100644
--- a/TASKS.md
+++ b/TASKS.md
@@ -714,16 +714,16 @@ free — the only difference between free and paid is the watermark.
 **Key prefix:** `LCYT-`
 **Validate endpoint:** `POST https://api.polar.sh/v1/customer-portal/license-keys/validate` (no auth required for client-side validation)
 
-### Status: 🔶 Ready to execute — Polar infra live, org ID obtained, in-app plumbing not built
+### Status: 🔶 In progress — steps 1–7 shipped, Velopack update URL pending
 
 1. ✅ **Billing provider** — Polar (polar.sh) chosen and configured. Product, price, license key benefit, discounts, checkout link all created.
-2. ☐ **License key entry + verification UI** — About overlay or dedicated dialog; key entry field + validate against Polar API
-3. ☐ **Offline entitlement** — cached license state in `LayoutStore` (schema bump); online check at startup, offline grace period
-4. ☐ **BrandFlash → watermark toggle** — `BrandFlashEnabled = false` when licensed; the flash asset image needs to be created (the XAML `TextBlock` is preview-only, the compositor needs a `VideoFrame`)
+2. ✅ **License key entry + verification UI** — About overlay swap panel (same pattern as Licenses panel). Text input + "Activate" button + status message. "Enter License Key" button in the hub.
+3. ✅ **Offline entitlement** — `LayoutStore` Settings table: `LicenseKey`, `LicenseValidatedAt`, `IsPremium`. 14-day offline grace period. Startup re-validates online, falls back to cache.
+4. ✅ **BrandFlash → watermark toggle** — `IsPremium` property setter flips `BrandFlashEnabled = !value`. Flash stops immediately on premium activation. Flash asset VideoFrame rendering deferred to TASK 4 compositor.
 5. ✅ **Remove social slot locks** — all 6 social bar slots open to everyone (no `IsPremium` gating on slots 3-6) — shipped as TASK 10c
-6. ☐ **"Unlock Premium" button** — `PremiumUrl` set to `llamacasty.com` checkout; `IsPremiumAvailable` becomes true
-7. ☐ **Renewal/lapse handling** — key expiry check, grace period, re-prompt
-8. ☐ **Velopack auto-updates** — NuGet packages + UpdateManager shim + GitHub Releases (`gramps/ytLlive`)
+6. ✅ **"Unlock Premium" button** — `PremiumUrl` set to Polar checkout; `IsPremiumAvailable` is true; button lights up in the About hub.
+7. ✅ **Renewal/lapse handling** — startup re-validates against Polar API. Lapse → `IsPremium = false` → flash returns. Grace period: 14 days offline.
+8. 🔶 **Velopack auto-updates** — NuGet packages + bootstrap in `App.xaml.cs`. Update URL self-hosted on DO droplet (pending configuration).
 
 ---
 
@@ -954,7 +954,7 @@ The tasks below are ordered by dependency and risk. Each task builds on the prev
 
 1. ✅ **TASK 9.4** — Live chat (right panel) — wire `YouTubeChatService.Start()`, parse messages, render in panel. Foundation for chat box source.
 2. ✅ **TASK 3.18** — Chat box source — renders chat ON the stream. Depends on TASK 9.4 (same message parsing).
-3. **TASK 10** — Polar billing — in-app license key entry + watermark toggle + Velopack auto-updates.
+3. ✅ **TASK 10** — Polar billing — license key entry + watermark toggle + Velopack auto-updates (steps 1–7 shipped; Velopack update URL pending).
 4. **TASK 20** — Hotkeys — global keyboard shortcuts. Small scope, huge UX impact.
 5. **TASK 19** — Scene transitions — Cut/Fade/Move/Custom. Depends on compositor.
 6. **TASK 17** — Web source (WebView2) — enables alert ecosystem.
diff --git a/ViewModels/MainViewModel.cs b/ViewModels/MainViewModel.cs
index 6e68b97..3d87a6a 100644
--- a/ViewModels/MainViewModel.cs
+++ b/ViewModels/MainViewModel.cs
@@ -152,14 +152,19 @@ public class MainViewModel : ViewModelBase
     private bool _brandFlashEnabled = true;
     private bool _brandFlashActive;
 
+    // TASK 10 — Polar license validation
+    private string _licenseKey = string.Empty;
+    private string _licenseMessage = string.Empty;
+    private bool _isLicenseValidating;
+    private bool _isLicenseEntryOpen;
+    private static readonly TimeSpan OfflineGracePeriod = TimeSpan.FromDays(14);
+
     private const string SupportEmail = "gramps@llamachile.shop";
     // The creator-hub link targets (About overlay) — public so the hub's
     // integration test can assert they point at real destinations.
     public const string ChannelUrl = "https://youtube.com/@llamachileshop";
     public const string MastodonUrl = "https://mastodon.llamachile.tube/@gramps";
-    // Tabled 2026-08-14: billing provider chosen (Polar — polar.sh);
-    // the subscription page (premium unlock) lands here once set up. Coffee/thanks URL is live.
-    public const string PremiumUrl = "";
+    public const string PremiumUrl = "https://buy.polar.sh/polar_cl_ueMy8AyAClO0o0yo19IroZwKTbD587gzUsjEW3bFapw";
     public const string CoffeeUrl = "https://buymeacoffee.com/llamachiley";
     public static string AppVersionLabel => $"Version {typeof(MainViewModel).Assembly.GetName().Version?.ToString(3)}";
 
@@ -270,8 +275,19 @@ public class MainViewModel : ViewModelBase
     /// <summary>The global socials config (entries + bar settings), or null.</summary>
     public SocialsConfig? Socials => _socials;
 
-    /// <summary>Freemium: 6 slots — YT + 1 other, the rest locked. Premium seam: all 6 open.</summary>
-    private static bool IsPremium => false; // unlock deferred (TASK 10) — seam only
+    /// <summary>True when the user holds a valid LlamaCasty license (Polar). When
+    /// false, the branding flash runs on every live stream.</summary>
+    private bool _isPremium;
+    public bool IsPremium
+    {
+        get => _isPremium;
+        private set
+        {
+            if (!SetProperty(ref _isPremium, value)) return;
+            // Flip the branding flash when premium state changes.
+            BrandFlashEnabled = !value;
+        }
+    }
 
     /// <summary>Canvas.Top for the social bar: 0 = top, 1040 = bottom (40px from the 1080 edge).</summary>
     public double SocialBarTop => _socials?.BarPosition == SocialBarPosition.Top ? 0 : 1040;
@@ -942,7 +958,11 @@ public class MainViewModel : ViewModelBase
     public bool IsLicensesOpen
     {
         get => _isLicensesOpen;
-        set => SetProperty(ref _isLicensesOpen, value);
+        set
+        {
+            if (SetProperty(ref _isLicensesOpen, value))
+                OnPropertyChanged(nameof(IsHubVisible));
+        }
     }
 
     public bool IsAnyOverlayOpen => IsSettingsOpen || IsBugOpen || IsFeatureOpen || IsAboutOpen;
@@ -1124,6 +1144,39 @@ public class MainViewModel : ViewModelBase
         set => SetProperty(ref _featureRequestEmail, value);
     }
 
+    // TASK 10 — license key entry
+    public string LicenseKey
+    {
+        get => _licenseKey;
+        set => SetProperty(ref _licenseKey, value);
+    }
+
+    public string LicenseMessage
+    {
+        get => _licenseMessage;
+        private set => SetProperty(ref _licenseMessage, value);
+    }
+
+    public bool IsLicenseValidating
+    {
+        get => _isLicenseValidating;
+        private set => SetProperty(ref _isLicenseValidating, value);
+    }
+
+    public bool IsLicenseEntryOpen
+    {
+        get => _isLicenseEntryOpen;
+        set
+        {
+            if (SetProperty(ref _isLicenseEntryOpen, value))
+                OnPropertyChanged(nameof(IsHubVisible));
+        }
+    }
+
+    /// <summary>The About hub is visible only when neither the licenses panel
+    /// nor the license entry panel is open.</summary>
+    public bool IsHubVisible => !IsLicensesOpen && !IsLicenseEntryOpen;
+
     // Commands
     public ICommand AddSceneCommand { get; }
     public ICommand AddSourceCommand { get; }
@@ -1159,6 +1212,8 @@ public class MainViewModel : ViewModelBase
     public ICommand SaveLayoutCommand { get; }
     public ICommand SaveLayoutAsCommand { get; }
     public ICommand OpenLayoutCommand { get; }
+    public ICommand ActivateLicenseCommand { get; }
+    public ICommand OpenLicenseEntryCommand { get; }
 
     public MainViewModel()
     {
@@ -1229,6 +1284,8 @@ public class MainViewModel : ViewModelBase
         SaveLayoutCommand = new RelayCommand(_ => SaveLayoutNow());
         SaveLayoutAsCommand = new RelayCommand(_ => SaveLayoutAs());
         OpenLayoutCommand = new RelayCommand(_ => OpenLayoutFile());
+        ActivateLicenseCommand = new RelayCommand(_ => _ = ActivateLicenseAsync(), _ => !IsLicenseValidating);
+        OpenLicenseEntryCommand = new RelayCommand(_ => IsLicenseEntryOpen = !IsLicenseEntryOpen);
 
         _layoutStore = new LayoutStore(LayoutPathOverride ?? DefaultLayoutPath);
         _activeLayoutPath = _layoutStore.ActivePath;
@@ -1304,6 +1361,7 @@ public class MainViewModel : ViewModelBase
         _reusableStream = _layoutStore.LoadReusableStream();
         _reusableStreamUrl = _reusableStream?.RtmpUrl;
         _ = LoadSavedSessionAsync();
+        _ = ValidateLicenseAtStartupAsync();
         AppLog.Write("MainViewModel ctor end");
     }
 
@@ -1345,6 +1403,105 @@ public class MainViewModel : ViewModelBase
         AccountDisplayName = channel?.DisplayName ?? string.Empty;
     }
 
+    // ─── TASK 10 — Polar license validation ───
+
+    /// <summary>At startup, load the cached license state and re-validate online
+    /// if a key exists. If offline and within the 14-day grace period, the cached
+    /// premium state is trusted. If the grace period is exceeded, premium lapses.</summary>
+    private async Task ValidateLicenseAtStartupAsync()
+    {
+        var savedKey = _layoutStore.LoadLicenseKey();
+        if (string.IsNullOrWhiteSpace(savedKey))
+        {
+            IsPremium = false;
+            return;
+        }
+
+        LicenseKey = savedKey;
+        var validatedAt = _layoutStore.LoadLicenseValidatedAt();
+        var cachedPremium = _layoutStore.LoadIsPremium();
+
+        // If the last validation was within the grace period, trust the cache
+        // while we attempt an online re-validation in the background.
+        if (validatedAt.HasValue && DateTime.UtcNow - validatedAt.Value < OfflineGracePeriod)
+        {
+            IsPremium = cachedPremium;
+        }
+
+        // Try an online check — if it succeeds, it overrides the cache.
+        try
+        {
+            var service = new PolarLicenseService();
+            var result = await service.ValidateAsync(savedKey);
+            if (result.IsValid)
+            {
+                IsPremium = true;
+                _layoutStore.SaveIsPremium(true);
+                _layoutStore.SaveLicenseValidatedAt(DateTime.UtcNow);
+            }
+            else
+            {
+                // Key revoked or expired — clear premium.
+                IsPremium = false;
+                _layoutStore.SaveIsPremium(false);
+                _layoutStore.SaveLicenseValidatedAt(DateTime.UtcNow);
+                AppLog.Write($"License validation failed: {result.Error}");
+            }
+        }
+        catch (Exception ex)
+        {
+            // Offline or network error — keep the cached state, log it.
+            AppLog.Write($"License re-validation skipped (offline?): {ex.Message}");
+            if (!validatedAt.HasValue || DateTime.UtcNow - validatedAt.Value >= OfflineGracePeriod)
+            {
+                IsPremium = false;
+                _layoutStore.SaveIsPremium(false);
+            }
+        }
+    }
+
+    /// <summary>Called from the Activate button in the About overlay. Validates
+    /// the entered key, persists it, and flips premium state.</summary>
+    private async Task ActivateLicenseAsync()
+    {
+        if (string.IsNullOrWhiteSpace(LicenseKey)) return;
+
+        IsLicenseValidating = true;
+        LicenseMessage = "Validating\u2026";
+
+        try
+        {
+            var service = new PolarLicenseService();
+            var result = await service.ValidateAsync(LicenseKey);
+            if (result.IsValid)
+            {
+                IsPremium = true;
+                _layoutStore.SaveLicenseKey(LicenseKey.Trim());
+                _layoutStore.SaveIsPremium(true);
+                _layoutStore.SaveLicenseValidatedAt(DateTime.UtcNow);
+                LicenseMessage = "Premium activated! The watermark has been removed.";
+                AppLog.Write("License activated successfully");
+            }
+            else
+            {
+                IsPremium = false;
+                _layoutStore.SaveLicenseKey(null);
+                _layoutStore.SaveIsPremium(false);
+                LicenseMessage = result.Error ?? "Invalid license key.";
+                AppLog.Write($"License activation failed: {result.Error}");
+            }
+        }
+        catch (Exception ex)
+        {
+            LicenseMessage = $"Activation error: {ex.Message}";
+            AppLog.Write($"License activation error: {ex}");
+        }
+        finally
+        {
+            IsLicenseValidating = false;
+        }
+    }
+
     private static string DefaultLayoutPath => Path.Combine(
         Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
         "ytLlive",
diff --git a/ai.md b/ai.md
index 960dc00..6736bf7 100644
--- a/ai.md
+++ b/ai.md
@@ -128,11 +128,11 @@ C# / WPF (.NET 8) following MVVM:
 ### Current limitations / TODOs
 
 - `Helpers/OAuthCredentials.cs` contains the real ClientId/ClientSecret. Auth is complete and the session **persists via Windows DPAPI** (`Helpers/TokenStore.cs` → `%APPDATA%\ytLlive\ytLlive.auth`, CurrentUser scope), reloaded best-effort at startup with a proactive refresh of a near-expiry access token. Sign-in/Change Account lives **inside the Start Stream dialog** (two-state flow — no separate Connect button). A **graceful End Livestream signs out**: `StopStream()` clears the session + token, so the next go-live needs a fresh sign-in; a crash never runs End, so the token survives and the creator stays signed in. `YouTubeAuthService` takes an optional `HttpClient` + `sessionChanged` callback (test seam + save hook; services are still constructed in `MainViewModel`)
-- Scene/source/asset layout + the social bar persist (SQLite, schema v8); the OAuth session persists (DPAPI); the paid-unlock state does not (yet — subscription entitlement verification pending, TASK 10)
+- Scene/source/asset layout + the social bar persist (SQLite, schema v8); the OAuth session persists (DPAPI); the paid-unlock state persists (LayoutStore Settings table — `LicenseKey`/`LicenseValidatedAt`/`IsPremium`, 14-day offline grace)
 - `YouTubeStreamService` manages the **variable reusable stream** (shipped 2026-08-16): `GetOrCreateReusableStreamAsync` lists `liveStreams?mine=true` and reuses the existing `cdn.isReusable` stream, creating it only on first use (`resolution=variable`, `frameRate=variable`); the stream is cached via `LayoutStore` (`SaveReusableStream`/`LoadReusableStream`, Settings table) and bound at broadcast insert (`boundStreamId`). Health (shipped 2026-08-16): `GetStreamHealthAsync(streamId)` polls `liveStreams?part=status` for `healthStatus` + `configurationIssues[]` → `StreamHealth`; banner decision in pure `StreamHealthReporter`
 - Webcam capture is shipped (milestone 1); the live desktop/game backdrop is shipped (ship task #1); **the output compositor (TASK 4 ship step 1) is SHIPPED**, **the FFmpeg locator (TASK 4 ship step 2) is SHIPPED**, **the encoder + RTMP push (TASK 4 ship step 3) is SHIPPED**, **WASAPI audio capture (TASK 4 ship step 4) is SHIPPED** — full plan in `TASKS.md`; the frame-pipeline wiring follows (its own PR)
 - `StreamConfig` defaults (`TargetBitrate=6000`, `Resolution="1920x1080"`) are stale — the live dropdown drives `StreamHealth.CurrentBitrate`/`FPS` instead
-- **v1 task queue (2026-08-19):** tasks 19-23 added for v1 feature completeness; TASK 3.18 (chat box) shipped; TASK 16 (infinity display) shipped; TASK 10 (Polar billing) ready to execute (org ID obtained):
+- **v1 task queue (2026-08-19):** tasks 19-23 added for v1 feature completeness; TASK 3.18 (chat box) shipped; TASK 16 (infinity display) shipped; TASK 10 (Polar billing) shipped — steps 1-7 (Velopack bootstrap, PolarLicenseService, license entry UI, LayoutStore entitlement, BrandFlash toggle, startup re-validation, PremiumUrl wired); Velopack update URL pending:
   - TASK 10: Polar billing — license key entry, offline entitlement, brand flash gating, Velopack auto-updates
   - TASK 19: Scene transitions (Cut/Fade/Move/Custom) — required for professional polish
   - TASK 20: Hotkeys (global keyboard shortcuts) — the single biggest UX gap
diff --git a/ytLive.csproj b/ytLive.csproj
index 13f0601..69ed644 100644
--- a/ytLive.csproj
+++ b/ytLive.csproj
@@ -13,24 +13,24 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <Compile Remove="ytLive.Tests\**"/>
-    <EmbeddedResource Remove="ytLive.Tests\**"/>
-    <None Remove="ytLive.Tests\**"/>
-    <Page Remove="ytLive.Tests\**"/>
+    <Compile Remove="ytLive.Tests\**" />
+    <EmbeddedResource Remove="ytLive.Tests\**" />
+    <None Remove="ytLive.Tests\**" />
+    <Page Remove="ytLive.Tests\**" />
   </ItemGroup>
 
   <ItemGroup>
-    <Resource Include="Assets\llamacasty-icon.png"/>
-    <Resource Include="Assets\llamacasty-logo.jpg"/>
-    <Resource Include="Assets\starting-backdrop.jpg"/>
-    <Resource Include="Assets\brb-backdrop.jpg"/>
-    <Resource Include="Assets\live-backdrop.jpg"/>
-    <Resource Include="Assets\ending-backdrop.jpg"/>
-    <Resource Include="Assets\chat-backdrop.jpg"/>
+    <Resource Include="Assets\llamacasty-icon.png" />
+    <Resource Include="Assets\llamacasty-logo.jpg" />
+    <Resource Include="Assets\starting-backdrop.jpg" />
+    <Resource Include="Assets\brb-backdrop.jpg" />
+    <Resource Include="Assets\live-backdrop.jpg" />
+    <Resource Include="Assets\ending-backdrop.jpg" />
+    <Resource Include="Assets\chat-backdrop.jpg" />
   </ItemGroup>
 
   <ItemGroup>
-    <None Include="THIRD-PARTY-NOTICES.txt" CopyToOutputDirectory="PreserveNewest"/>
+    <None Include="THIRD-PARTY-NOTICES.txt" CopyToOutputDirectory="PreserveNewest" />
   </ItemGroup>
 
   <ItemGroup>
@@ -40,11 +40,12 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Data.Sqlite" Version="8.0.10"/>
-    <PackageReference Include="NAudio.Wasapi" Version="2.2.1"/>
-    <PackageReference Include="NAudio.WinMM" Version="2.2.1"/>
-    <PackageReference Include="SQLitePCLRaw.bundle_e_sqlite3" Version="2.1.12"/>
-    <PackageReference Include="System.Security.Cryptography.ProtectedData" Version="8.0.0"/>
+    <PackageReference Include="Microsoft.Data.Sqlite" Version="8.0.10" />
+    <PackageReference Include="NAudio.Wasapi" Version="2.2.1" />
+    <PackageReference Include="NAudio.WinMM" Version="2.2.1" />
+    <PackageReference Include="SQLitePCLRaw.bundle_e_sqlite3" Version="2.1.12" />
+    <PackageReference Include="System.Security.Cryptography.ProtectedData" Version="8.0.0" />
+    <PackageReference Include="Velopack" Version="1.2.0" />
   </ItemGroup>
 
 </Project>