Social bar (Branch B): global resource with per-scene presence — Models/Socials.cs (19 services, icons, canonical URLs), Services/SocialValidator.cs (HTTP lookup validation seam), LayoutStore schema v7 (Socials + SocialEntry tables + Scene.HasSocialBar), MainViewModel (socials collection, AddSocial/RemoveSocial/ToggleSceneSocialBar commands, freemium cap YT+1, premium seam), MainWindow.xaml (footer Social button + [+/-] toggle on meter line, preview bar rendering top/bottom + LCR), 4 integration tests (roundtrip, empty-not-persisted, canonical URLs, icons), 85 tests passing, 0 warnings

Services/LayoutStore.cs

@@ -15,6 +15,9 @@ public class LayoutStore : IDisposable
     /// <summary>The app-wide webcam identity loaded with the last Load() (null = never picked).</summary>
     public Webcam? Webcam { get; private set; }
 
+    /// <summary>The app-wide social bar config loaded with the last Load() (null = never defined).</summary>
+    public SocialsConfig? Socials { get; private set; }
+
     public LayoutStore(string path)
     {
         ActivePath = path;
@@ -104,6 +107,23 @@ public class LayoutStore : IDisposable
                 PRIMARY KEY (SceneId, WebcamId)
             );
             """,
+            """
+            CREATE TABLE IF NOT EXISTS Socials (
+                Id TEXT PRIMARY KEY,
+                BarPosition TEXT NOT NULL DEFAULT 'Bottom',
+                BarJustify TEXT NOT NULL DEFAULT 'Center'
+            );
+            """,
+            """
+            CREATE TABLE IF NOT EXISTS SocialEntry (
+                Id TEXT PRIMARY KEY,
+                SocialsId TEXT NOT NULL REFERENCES Socials(Id) ON DELETE CASCADE,
+                Service TEXT NOT NULL,
+                Handle TEXT NOT NULL,
+                ProfileUrl TEXT NOT NULL,
+                SortOrder INTEGER NOT NULL DEFAULT 0
+            );
+            """,
         };
         foreach (var sql in statements)
         {
@@ -114,11 +134,12 @@ public class LayoutStore : IDisposable
         MigrateSourceTable();
         MigrateWebcamConfigTable();
         MigrateSceneTable();
+        MigrateSceneSocialBarColumn();
         if (GetUserVersion() < 3)
             MigrateToV3();
         using (var cmd = _connection.CreateCommand())
         {
-            cmd.CommandText = "PRAGMA user_version = 6;";
+            cmd.CommandText = "PRAGMA user_version = 7;";
             cmd.ExecuteNonQuery();
         }
     }
@@ -319,16 +340,37 @@ public class LayoutStore : IDisposable
         }
     }
 
+    // v6 → v7: Scene gains HasSocialBar (the per-scene social-bar toggle).
+    // Defaults to 0 (off) — the creator adds it explicitly via the footer [+].
+    private void MigrateSceneSocialBarColumn()
+    {
+        var columns = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        using (var cmd = _connection.CreateCommand())
+        {
+            cmd.CommandText = "PRAGMA table_info(Scene);";
+            using var reader = cmd.ExecuteReader();
+            while (reader.Read())
+                columns.Add(reader.GetString(1));
+        }
+
+        if (columns.Contains("HasSocialBar")) return;
+
+        using var alter = _connection.CreateCommand();
+        alter.CommandText = "ALTER TABLE Scene ADD COLUMN HasSocialBar INTEGER NOT NULL DEFAULT 0;";
+        alter.ExecuteNonQuery();
+    }
+
     public List<Scene> Load()
     {
         Webcam = null;
+        Socials = null;
         var scenes = new List<Scene>();
         var sourcesByScene = new Dictionary<string, List<Source>>();
         var configsByScene = new Dictionary<string, List<WebcamSceneConfig>>();
 
         using (var cmd = _connection.CreateCommand())
         {
-            cmd.CommandText = "SELECT Id, Name, IsHidden, IsChatScene, HasBackdrop FROM Scene ORDER BY SortOrder";
+            cmd.CommandText = "SELECT Id, Name, IsHidden, IsChatScene, HasBackdrop, HasSocialBar FROM Scene ORDER BY SortOrder";
             using var reader = cmd.ExecuteReader();
             while (reader.Read())
             {
@@ -339,6 +381,7 @@ public class LayoutStore : IDisposable
                     IsHidden = reader.GetInt32(2) != 0,
                     IsChatScene = reader.GetInt32(3) != 0,
                     HasBackdrop = reader.GetInt32(4) != 0,
+                    HasSocialBar = reader.FieldCount > 5 && !reader.IsDBNull(5) && reader.GetInt32(5) != 0,
                 });
             }
         }
@@ -358,6 +401,35 @@ public class LayoutStore : IDisposable
             }
         }
 
+        using (var cmd = _connection.CreateCommand())
+        {
+            cmd.CommandText = "SELECT Id, BarPosition, BarJustify FROM Socials LIMIT 1;";
+            using var reader = cmd.ExecuteReader();
+            if (reader.Read())
+            {
+                Socials = new SocialsConfig
+                {
+                    BarPosition = Enum.TryParse<SocialBarPosition>(reader.GetString(1), out var pos) ? pos : SocialBarPosition.Bottom,
+                    BarJustify = Enum.TryParse<SocialBarJustify>(reader.GetString(2), out var just) ? just : SocialBarJustify.Center,
+                };
+                var socialsId = reader.GetString(0);
+
+                using var entryCmd = _connection.CreateCommand();
+                entryCmd.CommandText = "SELECT Service, Handle, ProfileUrl FROM SocialEntry WHERE SocialsId = $id ORDER BY SortOrder;";
+                entryCmd.Parameters.AddWithValue("$id", socialsId);
+                using var entryReader = entryCmd.ExecuteReader();
+                while (entryReader.Read())
+                {
+                    Socials.Entries.Add(new SocialEntry
+                    {
+                        Service = Enum.TryParse<SocialService>(entryReader.GetString(0), out var svc) ? svc : SocialService.Link,
+                        Handle = entryReader.GetString(1),
+                        ProfileUrl = entryReader.GetString(2),
+                    });
+                }
+            }
+        }
+
         using (var cmd = _connection.CreateCommand())
         {
             cmd.CommandText = """
@@ -444,7 +516,7 @@ public class LayoutStore : IDisposable
         return scenes;
     }
 
-    public void Save(IEnumerable<Scene> scenes, Webcam? webcam)
+    public void Save(IEnumerable<Scene> scenes, Webcam? webcam, SocialsConfig? socials)
     {
         using var tx = _connection.BeginTransaction();
         using (var cmd = _connection.CreateCommand())
@@ -466,6 +538,18 @@ public class LayoutStore : IDisposable
             cmd.ExecuteNonQuery();
         }
         using (var cmd = _connection.CreateCommand())
+        {
+            cmd.CommandText = "DELETE FROM SocialEntry;";
+            cmd.Transaction = tx;
+            cmd.ExecuteNonQuery();
+        }
+        using (var cmd = _connection.CreateCommand())
+        {
+            cmd.CommandText = "DELETE FROM Socials;";
+            cmd.Transaction = tx;
+            cmd.ExecuteNonQuery();
+        }
+        using (var cmd = _connection.CreateCommand())
         {
             cmd.CommandText = "DELETE FROM Scene;";
             cmd.Transaction = tx;
@@ -475,8 +559,8 @@ public class LayoutStore : IDisposable
         using (var cmd = _connection.CreateCommand())
         {
             cmd.CommandText = """
-                INSERT INTO Scene (Id, Name, IsHidden, IsChatScene, HasBackdrop, SortOrder)
-                VALUES ($id, $name, $isHidden, $isChat, $hasBackdrop, $sort)
+                INSERT INTO Scene (Id, Name, IsHidden, IsChatScene, HasBackdrop, HasSocialBar, SortOrder)
+                VALUES ($id, $name, $isHidden, $isChat, $hasBackdrop, $hasSocialBar, $sort)
                 """;
             cmd.Transaction = tx;
             var idP = cmd.Parameters.Add("$id", SqliteType.Text);
@@ -484,6 +568,7 @@ public class LayoutStore : IDisposable
             var hiddenP = cmd.Parameters.Add("$isHidden", SqliteType.Integer);
             var chatP = cmd.Parameters.Add("$isChat", SqliteType.Integer);
             var backdropP = cmd.Parameters.Add("$hasBackdrop", SqliteType.Integer);
+            var socialBarP = cmd.Parameters.Add("$hasSocialBar", SqliteType.Integer);
             var sortP = cmd.Parameters.Add("$sort", SqliteType.Integer);
 
             var sort = 0;
@@ -494,6 +579,7 @@ public class LayoutStore : IDisposable
                 hiddenP.Value = scene.IsHidden ? 1 : 0;
                 chatP.Value = scene.IsChatScene ? 1 : 0;
                 backdropP.Value = scene.HasBackdrop ? 1 : 0;
+                socialBarP.Value = scene.HasSocialBar ? 1 : 0;
                 sortP.Value = sort++;
                 cmd.ExecuteNonQuery();
             }
@@ -626,6 +712,45 @@ public class LayoutStore : IDisposable
             }
         }
 
+        if (socials != null && socials.Entries.Count > 0)
+        {
+            var socialsId = Guid.NewGuid().ToString();
+            using (var cmd = _connection.CreateCommand())
+            {
+                cmd.CommandText = "INSERT INTO Socials (Id, BarPosition, BarJustify) VALUES ($id, $pos, $just);";
+                cmd.Transaction = tx;
+                cmd.Parameters.AddWithValue("$id", socialsId);
+                cmd.Parameters.AddWithValue("$pos", socials.BarPosition.ToString());
+                cmd.Parameters.AddWithValue("$just", socials.BarJustify.ToString());
+                cmd.ExecuteNonQuery();
+            }
+
+            using var entryCmd = _connection.CreateCommand();
+            entryCmd.CommandText = """
+                INSERT INTO SocialEntry (Id, SocialsId, Service, Handle, ProfileUrl, SortOrder)
+                VALUES ($id, $socialsId, $service, $handle, $url, $sort)
+                """;
+            entryCmd.Transaction = tx;
+            var eId = entryCmd.Parameters.Add("$id", SqliteType.Text);
+            var eSocialsId = entryCmd.Parameters.Add("$socialsId", SqliteType.Text);
+            var eService = entryCmd.Parameters.Add("$service", SqliteType.Text);
+            var eHandle = entryCmd.Parameters.Add("$handle", SqliteType.Text);
+            var eUrl = entryCmd.Parameters.Add("$url", SqliteType.Text);
+            var eSort = entryCmd.Parameters.Add("$sort", SqliteType.Integer);
+
+            var entrySort = 0;
+            foreach (var entry in socials.Entries)
+            {
+                eId.Value = Guid.NewGuid().ToString();
+                eSocialsId.Value = socialsId;
+                eService.Value = entry.Service.ToString();
+                eHandle.Value = entry.Handle;
+                eUrl.Value = entry.ProfileUrl;
+                eSort.Value = entrySort++;
+                entryCmd.ExecuteNonQuery();
+            }
+        }
+
         using (var cmd = _connection.CreateCommand())
         {
             cmd.CommandText = "DELETE FROM Asset WHERE Id NOT IN (SELECT AssetId FROM Source WHERE AssetId IS NOT NULL);";

Services/SocialValidator.cs

@@ -0,0 +1,82 @@
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using ytLive.Models;
+
+namespace ytLive.Services;
+
+public sealed class SocialLookupResult
+{
+    public bool Success { get; init; }
+    public string ProfileUrl { get; init; } = string.Empty;
+    public string Handle { get; init; } = string.Empty;
+    public string Error { get; init; } = string.Empty;
+}
+
+public interface ISocialValidator
+{
+    Task<SocialLookupResult> LookupAsync(SocialService service, string handleOrUrl);
+}
+
+/// <summary>
+/// Validates a social handle/URL by constructing the canonical profile URL and
+/// issuing an HTTP GET — the "act of validation" the creator trusts before the
+/// icon lands on their bar. Best-effort: some platforms return challenges/blocks
+/// to HEAD requests, so a 200 OR a 301/302 redirect counts as "exists"; 404 or
+/// connection failure = rejected. Never blind trust.
+/// </summary>
+public sealed class HttpSocialValidator : ISocialValidator
+{
+    private readonly HttpClient _client;
+
+    public HttpSocialValidator(HttpClient? client = null)
+    {
+        _client = client ?? new HttpClient();
+        _client.DefaultRequestHeaders.UserAgent.ParseAdd(
+            "Mozilla/5.0 (compatible; ytLlive social validator)");
+    }
+
+    public async Task<SocialLookupResult> LookupAsync(SocialService service, string handleOrUrl)
+    {
+        var input = handleOrUrl.Trim();
+        if (string.IsNullOrWhiteSpace(input))
+            return new SocialLookupResult { Error = "Enter a handle or URL." };
+
+        var handle = input;
+        if (input.StartsWith("http://", System.StringComparison.OrdinalIgnoreCase) ||
+            input.StartsWith("https://", System.StringComparison.OrdinalIgnoreCase))
+        {
+            var uri = new System.Uri(input);
+            handle = uri.AbsolutePath.Trim('/');
+        }
+
+        var url = SocialServiceIcons.CanonicalUrlFor(service, handle);
+
+        try
+        {
+            using var resp = await _client.GetAsync(url, CancellationToken.None);
+            if (resp.IsSuccessStatusCode || (int)resp.StatusCode is 301 or 302 or 303 or 307 or 308)
+                return new SocialLookupResult
+                {
+                    Success = true,
+                    ProfileUrl = url,
+                    Handle = handle.TrimStart('@'),
+                };
+            return new SocialLookupResult
+            {
+                Error = $"{service} returned {resp.StatusCode} for '{handle}'. The handle may be wrong or the page doesn't exist.",
+            };
+        }
+        catch (System.Net.Http.HttpRequestException)
+        {
+            return new SocialLookupResult
+            {
+                Error = $"Couldn't reach {service} to validate '{handle}'. Check your connection and try again.",
+            };
+        }
+        catch (System.Exception ex)
+        {
+            return new SocialLookupResult { Error = ex.Message };
+        }
+    }
+}

Services/index.md

@@ -32,6 +32,7 @@ External-facing logic: YouTube API, persistence. See
 | `Compositor/StretchMath.cs` | Pure pixel math: the WPF `UniformToFill` cover-crop, clamped bilinear sample/scale (unit-tested half of the compositor) |
 | `Compositor/StaticPixelCache.cs` | Asset bytes → cached BGRA8 `VideoFrame`, decoded once per content hash — the output path's raw-pixel source (the preview uses ImageCache's `BitmapImage`) |
 | `Encoder/IFfmpegLocator.cs` | **TASK 4 ship step 2 seam**: resolves an absolute path to `ffmpeg.exe` (PATH first → cached `%APPDATA%\ytLlive\tools\ffmpeg.exe` → pinned BtbN LGPL-shared zip download). The encoder step and tests fake it |
+| `SocialValidator.cs` | `ISocialValidator` seam + `HttpSocialValidator` default: validates a social handle/URL by constructing the canonical profile URL and issuing an HTTP GET — the "act of validation" before adding to the bar. 200/redirect = exists; 404/connection failure = rejected. Constructor takes optional `HttpClient` for tests |
 | `Encoder/FfmpegLocator.cs` | The default locator: PATH probe wins, then the cache, then pull+extract (`ffmpeg.exe` **+ the `libav*.dll` family** via a staging dir, failures via `AppLog`). Pinned to BtbN `autobuild-2026-08-09-13-03` **lgpl-shared** (dynamic linking = LGPL compliance without static-relink §6 material; no GPL libx264; NVENC/QSV/AMF + libopenh264 + native AAC — see `ai.md` → Licensing). Search dirs / tools dir / downloader constructor-injected for hermetic tests. Not yet constructed by the app (the encoder step wires it) |
 
 Related: constructed in [`ViewModels/MainViewModel.cs`](../ViewModels/MainViewModel.cs)