Update Windows and Linux FFmpeg source locks to BtbN 8.1.2-22-g94138f6973 from autobuild-2026-07-06-14-19.
Replace the bundled macOS Apple Silicon FFmpeg binary with Martin Riedl snapshot N-125450-gfad2e0bc50 and record its verified checksum.
Teach the update checker to compare FFmpeg provider builds separately from upstream stable releases so future refreshes are not missed.
Keep yt-dlp pinned at the current official stable 2026.07.04 and update Vitest to 4.1.10 so the release update gate stays clean.
- update npm dependencies, including Vite 8.1.0 and TypeScript 6.0.3
- update bundled Deno engine locks and macOS arm64 binary to 2.8.3
- add npm run check:updates for npm and engine freshness checks
- ignore local agent/planning notes and remove tracked internal docs
NimBold