[github-actions]

Assessed all 20 pinned branch snapshots from @3Ryuusei3, @shininchi and @Tycorc. Each now has a recorded decision and links to the relevant USCE work.

Source	Outcome
3Ryuusei3: Karaoke and engine changes	Optional theme in UltraStar-CE/Themes#16, reusable primitives in #211. Background-decoder work remains deferred in favor of #173, as decided in #210.
shininchi: songbook, queues, mic controls and achievements	Existing #168/usrelay route. Shared branch history is assessed once; no parallel server is imported.
shininchi: standalone deltas	Artist jumps #236; editor microphone capture #237; planar-audio crash investigation #238; worker-thread exception logging #239; optional gap countdown #240; macOS key artwork #241; local signing identity #242.
shininchi: generator/download changes	Not adopted, following the decisions in #202, #203 and #183. Editor pitch-preview work remains in #88.
Tycorc: MPV and newer fixes	Existing #173 and #164. The missing EOF-without-frame fix is recorded on #173; Windows benchmark/build and issue-form work stays in #166.
Tycorc: old branches	Existing AUDIO/help support and Homebrew caching are recorded as covered. Historical debug/formatting patches and the embedded web server are not adopted. Old audio changes are superseded by current USCE behavior. The SDL experiment remains tracked in #165.

The complete branch-by-branch assessment is in doc/upstream/usdx-forks.json, with the original snapshot heads preserved. #183 links the new follow-ups.

This completes triage, not implementation or runtime acceptance. No fork code was executed or imported. Fork-reported failures still need reproduction in USCE.

Unavailable source: danhale93/USDX-DeepStream was not assessed.