fix: Update platform-tools checksums and add WebRTC builds for all platforms

Platform Tools Checksum Updates:
- Fix Windows platform-tools r36.0.0 checksum in adb_windows.sh
- Fix macOS platform-tools r36.0.0 checksum in adb_macos.sh
- Verify Linux checksum (already correct)

WebRTC Build Support:
- Add WebRTC build jobs for Windows (32/64-bit) with MinGW cross-compilation
- Add WebRTC build jobs for macOS (ARM64/x86_64) with native compilation
- Add libdatachannel dependency installation for all WebRTC builds
- Add packaging jobs for all WebRTC builds with proper artifact handling
- Update release workflow to include all WebRTC builds and downloads
- Update WebRTC documentation to list all available platform builds

Build Outputs:
- scrcpy-webrtc-{version}-linux-x86_64.tar.gz
- scrcpy-webrtc-{version}-win32.zip
- scrcpy-webrtc-{version}-win64.zip
- scrcpy-webrtc-{version}-macos-aarch64.tar.gz
- scrcpy-webrtc-{version}-macos-x86_64.tar.gz

This resolves CI/CD checksum verification failures and enables WebRTC
streaming support across all major platforms, allowing users to control
Android devices directly from web browsers without client installation.

Author: nguyendkn