Build: require 64-bit Windows — PlatformTarget x64 in app + tests (bundled ffmpeg is win64, ONNX Runtime has no win-x86, 32-bit address space can't hold 1080p buffers) (Unit: 64-bit requirement)

HANDOFF.md

@@ -30,10 +30,13 @@
   fixtures in `ytLive.Tests/Fixtures/`).
 
 ## Known issues / follow-ups
+- **64-bit only (2026-10-09):** `PlatformTarget=x64` in both csproj files (verified: ytLive.dll PE
+  machine 0x8664, 408/408 green). TASK 48 item 2 carries the x64-only MSIX + `-r win-x64` publish.
 - `onnxruntime.dll` is ~17 MB; an RID-less build copies every RID's native folder — TASK 48's MSIX
   publish must pin win-x64.
-- `THIRD-PARTY-NOTICES.txt` header still says "paid, closed-source product" (pre free-forever) — noted,
-  not changed (out of scope).
+- `THIRD-PARTY-NOTICES.txt` header + ai.md Licensing/packaging sections still say "paid,
+  closed-source" / Store IAP / branding-flash paid delta (pre free-forever + planned public GPL-3.0
+  release) — the creator is choosing the license; rewrite those with it.
 - Carried: "Use default background" toggle still not working (from 2026-10-07).
 
 ## Next step