Standalone binaries for Windows & Arch (CI build matrix)

[gluckdev]

Summary

The Ubuntu one-file binary is done (CastToTV-linux.spec, ~124 MB, ffmpeg + yt-dlp + Chromecast/AirPlay/Pillow bundled, verified running with an empty PATH). Bring the same self-contained build to Windows and Arch Linux, and wire it into CI so a tagged push produces all three.

Scope

• Windows .exe: PyInstaller one-file bundling ffmpeg.exe + ffprobe.exe + yt-dlp.exe (via --add-binary), console=False, upx_exclude for ffmpeg. resolve_binary() already finds them in sys._MEIPASS.
• Arch: either the same PyInstaller one-file built in an Arch container, or a PKGBUILD that depends on Arch's system ffmpeg/yt-dlp (the resolve_binary() PATH fallback makes the lite build work without bundling).
• CI: a .github/workflows matrix (windows-latest / ubuntu-latest / arch container) that builds each on tag and attaches the artifacts to the release.

Notes

• Build on the oldest glibc target for Linux (Ubuntu LTS) so the binary also runs on Arch.
• Fat bundle is ~120–180 MB; consider also publishing a "lite" build (no bundled ffmpeg/yt-dlp, PATH-resolved) for users who have them.

Acceptance

• CastToTV.exe runs on a clean Windows machine, no Python/ffmpeg/yt-dlp installed.
• Arch build (binary and/or PKGBUILD) documented and working.
• CI matrix builds all three on tag and uploads release assets.