v2.3.3 - Performance, Command Palette & Atomic Updates

Performance

• Optimized orchestration dispatch and memory usage, cutting per-song working-set growth and reducing RSS memory during long playbacks.
• Released per-song resources and unused memory back to the OS after playback, stabilizing the footprint across repeated sessions.
• Hardened the real-time dispatch path with power throttling management and residual bias handling so input timing stays deterministic under load.

Features

• Rebuilt the command palette with modern navigation and localized the UI to English; added a manual update check.
• Implemented robust atomic updates with persistent version tracking and a safe manual fallback, plus auto-apply update configuration and status indicators.
• Added an update settings modal and silent background update checks.
• Introduced the MetadataHandle interface and refactored app state management around it.
• Added the PickerScreen for song selection and configuration.
• Added an example configuration file to document application settings.

Telemetry & Diagnostics

• Extended BackendHealth with keys_dropped and chord_split_events, plus a retain_records_after_save option to preserve telemetry records post-save.
• Enhanced send diagnostics to track dropped and retried keys; added abort-reason telemetry and focus-input lifecycle tests.

Fixes

• Fixed modal focus leakage from CommandModal dismiss callbacks.
• Restored search match highlighting in the song picker.
• Escaped Rich markup and consolidated duplicate CSS in the footer.

Build & Tooling

• Added uv env config, free-threaded wheel audit, and stdlib prune to the release pipeline.
• Added the packaging dependency and centralized versioning logic across pyproject.toml, uv.lock, and _version.py.