[sounak1125]

Concurrent saves from separate windows could overwrite image bytes or roll back another completed save. Reserve each board path throughout initialization, commit, compaction, and rollback, and add deterministic concurrency regression coverage. Failed installer attempts now retry correctly without stale completion state.

Upgrade the app and bootstrapper from Electron 37.10.3 to 44.4.5, migrate clipboard operations to the asynchronous API, and replace the outdated icon converter. Update dependencies and lockfiles; both npm audits report zero vulnerabilities. Remove unused renderer helpers, obsolete menu code, and stale content-aware UI smoke scripts; test the active snapping behavior instead.

Validation:

• Full npm test suite, including save concurrency, installer retry, and clipboard bridge regressions.
• Electron 44.4.5 desktop smoke checks for board I/O, clipboard roundtrip, snapping, note layout, rotation, split view, pinning, save abort, and multi-window history.
• Windows unpacked build and packaged-source verification.
• npm audit for the app and bootstrapper: zero vulnerabilities.