TASK 4 ship step 5.5: social bar bug fixes + bar on the live output — direction-snap drag (SocialBarSnap.Decide + ClearValue, local Canvas.Top was overriding the binding), fediverse nodeinfo subdomain probing + load-time heal (settable FediverseSoftware), SocialBarRenderer strip blitted above the flash via a re-read FramePump socialBar seam — 155 tests passing, 0 warnings

TASKS.md

@@ -475,6 +475,46 @@ added, `MainViewModel` wired end-to-end (resolver + both option builders + pump
 the pump reads the active scene on a background thread while the UI can still edit it; a concurrent-mutation
 exception is contained (logged + `Failed` + pump stops) rather than crashing.
 
+#### Ship step 5.5 — Social bar bug fixes + the bar on the live output (2026-08-13)
+
+**Bug 1 — drag doesn't snap (root cause found):** `SocialBar_PreviewMouseMove` set `Canvas.SetTop(bar, …)`
+with a local value, which permanently overrides the `Canvas.Top="{Binding SocialBarTop}"` binding — the
+release-time `SetSocialBarPosition` → `PropertyChanged(SocialBarTop)` could never beat it, so the bar stayed
+wherever it was dropped. Fixed by direction-snapping **during** the drag (`SocialBarSnap.Decide` — deadzone
+±6px, once the direction commits the bar rides the edge it's dragged toward, never mid-screen) and on release
+`bar.ClearValue(Canvas.TopProperty)` re-engages the binding before `SetSocialBarPosition`.
+
+**Bug 2 — Mastodon showed the generic 7-star honeycomb (root cause found):** the DB row
+`@gramps@llamachile.tube` had `Software = NULL` — nodeinfo was only ever resolved against the identity domain
+(`llamachile.tube`, a landing page), never probed for the real instance at `mastodon.llamachile.tube`.
+Fixed on three fronts: `HttpSocialValidator` now **probes well-known subdomains** (mastodon. → social. →
+… `FediverseSubdomainCandidates`) when the identity domain and its redirect both come up empty, under a
+~15s linked-CTS budget, with an optional `Action<string>` log; `MainViewModel` **heals** any fediverse entry
+missing a software name on layout load (`HealFediverseSoftwareAsync` — static, testable; instance wrapper
+runs it off the UI thread, applies via the dispatcher, saves); `SocialEntry.FediverseSoftware` is now
+**settable** and raises `PropertyChanged` for `LogoData`, so the heal updates the icon in place. If the user
+later re-saves the entry with the icon fixed, the name persists with it.
+
+**Compositor rendering (user-approved scope):** the social bar now appears **on the live output**, not just
+the preview — `Compositor/SocialBarRenderer.cs` rasterizes the entries into a transparent straight-alpha
+BGRA strip (1920-wide, 40px content + 24px glow pad, green `#2ecc71` glow baked in) via `RenderTargetBitmap`
+(WPF glue like `StaticPixelCache`; the compositor core stays pure). `SceneCompositor.Render` takes optional
+`socialBarFrame` + `socialBarTop` (master space) and blits it **last — above the branding flash** (the old
+`BlitFlash` generalized to offset `BlitOverlay`). `FramePump` gains a `socialBar:` seam
+(`Func<(VideoFrame?, SocialBarPosition)>`, re-read every frame) and places the bar at `0` or
+`SourceRectHeight − bar height`. `MainViewModel` owns the frame (`RenderSocialBarFrame`, re-rendered on
+load/save/notify) and feeds the seam.
+
+**Tests (+8 → 155 passing, 0 warnings):** `SocialBarSnap.Decide` units (direction + deadzone + custom
+deadzone), settable `FediverseSoftware` updates `LogoData`, subdomain-probe unit + null-when-silent unit,
+the branch's **one integration test** `Socials_HealMissingFediverseSoftware_RoundTripsThroughDb`
+(temp-DB roundtrip: NULL software → healed via the validator → persisted), compositor bar overlay
+(top/bottom + above-flash), `FramePump` bar pass-through (Top then flipped to Bottom mid-run — the seam is
+re-read each frame), and both `ISocialValidator` fakes (`FakeValidator`/`BlockingValidator`) gained
+`ResolveFediverseSoftwareAsync`.
+
+**Not included (say the word):** rewriting the healed entry's `ProfileUrl` to `https://mastodon.llamachile.tube/@gramps`.
+
 ---
 
 ## TASK 5 — YouTube Live Stream Management