docs(handoff): session-end refresh — HEAD 75723ac, attainability refinement, tree clean

HANDOFF.md

@@ -1,12 +1,22 @@
-# HANDOFF — 2026-09-17 (webcam app-default gate slice; committed locally — no push)
+# HANDOFF — 2026-09-17 (webcam attainability refinement committed locally at `75723ac` — no push)
 
 ## Branch / Commit State
 
-`main` HEAD = **`1e4017d` webcam startup resource lifecycle** (local). The gate slice lands
-on top as a NEW commit (stays commit-local until greenlight). Below: `94a934f` (reader-ladder),
-`64a5a6d` (slice-18 C4 cache), slice-17, slice-16, slice-15, `c01206f`, `b22d08e` (signed
-audio-sync, pushed). No push after this commit either — still awaiting the device take + user
-greenlight.
+`main` HEAD = **`75723ac` fix(webcam): offer the Web Cam row only when a camera is attainable
+(live lock), not merely selected** (local). Below it:
+
+- `9d00955` feat(webcam): app-default gate slice — per-scene offer, Add places default directly,
+  identity survives removal
+- `1e4017d` feat(webcam): resource lifecycle startup slice — poll-on-start, single-cam lock,
+  persistent Layers alert
+- `94a934f` reader-output-subtype ladder + WinRT per-call wrap rule
+- `64a5a6d` slice-18 C4 blit-on-change composite cache
+- `b37b8a3` slice-17 overlap GPU readbacks with monotonic publish gate
+
+**No push yet** — still awaiting the device take + user greenlight. Working tree clean.
+
+> Correcting the previous handoff, which still listed HEAD as `1e4017d`: the gate slice
+> (`9d00955`) and its attainability refinement (`75723ac`) are both committed now.
 
 ## ⚠️ Branding (2026-09-14, creator-corrected): product = **llamacasty**, internals = ytLive
 
@@ -14,7 +24,7 @@ Product is **llamacasty**; repo path, csproj `AssemblyName`/`RootNamespace`, DB/
 (`%APPDATA%\ytLlive\...`), most code names are legacy **ytLive/ytLlive**. User-facing text:
 "llamacasty" / UI labels use the catalog names ("Web Cam", "YouTube Chat", "Countdown Timer"…).
 
-## ✅ Committed — webcam app-default gate slice (creator-visible goal: Web Cam offered when switching to Live)
+## ✅ Committed — webcam app-default gate + attainability (`9d00955`, `75723ac`)
 
 **Background:** the DB truth (`%APPDATA%\ytLlive\ytLlive.db`; NOT `layout.db`, a 0-byte legacy
 file) put the single `WebcamSceneConfig` in **Chat**, so the old TASK 26 app-wide rule grayed
@@ -26,7 +36,7 @@ the availability layer. TASK 26's app-wide gate is **superseded** by creator dir
 - **Per-scene gate:** `CanAddWebcam` = `StagedScene is { WebcamConfig: null } && IsWebcamAttainable`.
   A scene already hosting the webcam stays gray (one webcam per stream); another scene holding it
   does NOT gray the row elsewhere.
-- **Attainable = a live lock, not a saved identity** (creator refinement): `IsWebcamAttainable` =
+- **Attainable = a live lock, not a saved identity** (`75723ac` refinement): `IsWebcamAttainable` =
   `_webcam != null && CameraManager.IsRunning(_webcam.DeviceId)`. An identity whose camera is
   unplugged / can't start leaves the row greyed (tooltip "No webcam is currently available…"), and
   it un-greys the moment a session is running (startup lock, first frame, picker + acquire).