Unit 2 of slimming the mandatory read. Verbatim move again - the four capture
blocks leave ai.md unchanged in content, and one stub carries the law.
- docs/ai/capture.md: 'Screen backdrop capture', 'Webcam capture', 'Webcam
background effects' and 'Vertical (9:16) tier camera placement', byte-
identical, grouped under backdrop / webcam / vertical headings, with a
'Related in ai.md' footer.
- ai.md stub keeps: the locked-Background model and NormalizeBackgrounds;
ActiveBackgroundImage is fed by static art only (2026-08-23 regression);
window:/picker: keys are session-scoped and a live pin beats auto-detect;
the settled WinRT interop paths (TryGetDataUnsafe, from-DXGIDevice); the
VideoFrame seam, own-catch subtype ladder and no fallback camera; one app-
level webcam identity with live-lock attainability; CameraManager as the one
effects processing point with per-session mask smoothing; geometry-only
vertical tier and the model-level rect lock.
- docs/ai/index.md gains the capture.md row; Services/index.md (2) and
TASKS/task-38-window-backdrop.md repointed.
ai.md 1,975 -> 1,558 lines. No source touched; no push.
Click-to-pin an open window as the full-bleed Live backdrop, via the existing
window:<hwnd> capture path (same render layer as game/desktop). Session-scoped:
window:/picker: keys heal to auto on reload (HWND-recycle hazard); pin wins
while the window enumerates, then auto-fallbacks (game → desktop → static); a
dead window's capture session heals to auto, no dead ends.
Fix: ScreenCaptureSourceFactory.Resolve hex-parsed "window:0x<Hwnd>" WITHOUT
stripping the 0x prefix — NumberStyles.HexNumber rejects it, so every pin
resolved null ("No capture target for this key") and the heal silently rolled
back. Same flaw in IsAliveWindowPin (pin-wins guard was dead). Both fixed.
Commit also carries an out-of-scope prerequisite: PillRadioTests.cs:105 had a
committed stray token ("...PrimaryStartButtonLabel soil;", CS1003) blocking the
whole test-project compile — token removed.
Plus the previous session's uncommitted pricing docs (one-time $29/$49) that
share TASKS.md/ai.md/HANDOFF.md.