Fix macOS edge resize capture

[AreChen]

Summary

• Detect macOS resize edges from the full transparent overlay using pointer coordinates instead of relying only on narrow transparent hit divs.
• Capture edge pointerdown before the drag-region starts native window dragging, and keep manual resize moving with the captured direction after the pointer leaves the edge zone.
• Prevent global pointerout handling from clearing resize feedback while the pointer remains on a resize edge.

Test Plan

• npm run verify:shell
• npm run build
• npm run tauri:build -- --config src-tauri/tauri.macos.conf.json --bundles app
• node scripts/bundle-macos-libmpv.mjs && codesign --force --deep --sign - ../../target/release/bundle/macos/OpenPlayer.app && codesign --verify --deep --strict --verbose=2 ../../target/release/bundle/macos/OpenPlayer.app
• cargo test -p openplayer-desktop
• find target/release/bundle/macos/OpenPlayer.app/Contents -type f ( -name '*.dylib' -o -perm +111 ) -print0 | xargs -0 otool -L 2>/dev/null | rg '/opt/homebrew|/usr/local' || true
• git diff --check