v1.3.2 — Ad-hoc signing + one-click install.command

Distribution hardening (free tier — no paid Apple Developer account).

Added

• Ad-hoc code signing on every build (codesign --deep --force --sign -). Does NOT make Gatekeeper trust the app (that requires a
  paid Developer ID + notarization), but it gives the binary a valid
  internal signature so open stops logging "broken signature"
  warnings and macOS doesn't re-classify the bundle on every launch.
• One-click installer bundle dist/CCCPlayer-<ver>-arm64-install.zip
  containing:
  • CCCPlayer.app (ad-hoc signed)
  • install.command — double-click script that clears the
    com.apple.quarantine xattr, copies the app to /Applications,
    and launches it. User still has to right-click → Open the first
    time to clear Gatekeeper's warning on the script itself, but
    that's one confirmation vs. typing xattr by hand.
  • README.txt with three alternate install paths (install.command
    / right-click Open / Terminal xattr).
• README now documents the three install options clearly in both EN
  and ZH sections.

Not done (intentional)

• No notarization. Requires an Apple Developer Program membership
  ($99/year). If you set one up: swap --sign - in build-macos.sh
  for "Developer ID Application: <Your Name>" and add
  xcrun notarytool submit ... --wait && xcrun stapler staple after
  the dmg is produced.