CARGO_PKG_VERSION is always 0.1.0 (hardcoded in Cargo.toml). CI
patches tauri.conf.json from the git tag. Now reads app_handle.config()
for the real version so the update checker compares correctly.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Checks Gitea releases API for latest version on startup. If newer
version available, shows confirm dialog to open download page.
Also adds "Check for Updates" button in Settings → About with
version comparison, release notes display, and download button.
Backend: check_for_updates command with semver comparison (6 tests).
96 total tests, zero warnings.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>