feat: add desktop auto-update flow

[juacker]

Summary

• Add a persisted auto-update setting, enabled by default, with About settings UI for support status, manual checks, and install/restart.
• Add backend updater commands, startup background checks, update-available events, install progress events, and platform/package support detection.
• Gate unsupported/external package flows such as dev builds, Flatpak, mismatched Linux package-manager installs, and missing native bundle metadata.
• Serialize ts-rs binding generation to avoid parallel export tests truncating src/generated/bindings.ts.

Verification

• cargo test --lib -- --test-threads=1 (826 tests)
• cargo fmt --check
• cargo check
• cargo test --lib app_updates
• npm run gen:bindings
• npm run typecheck
• npm run lint
• npm run build
• npm test (179 tests; existing act/canvas warnings)
• git diff --check HEAD

Review

• Independent final source-only review: production_quality, no blocker/major findings.
• Fixed validated reviewer findings: About toggle save rollback race and unbounded artifact download timeout.

Notes

• macOS updater availability still depends on release metadata publishing darwin-* updater entries.
• Flatpak and package-manager-managed installs report as externally managed instead of attempting native self-update.

[juacker]

Added notify-only update checks for Flatpak builds (372f908): CLAI's Flatpak is a side-loaded bundle with no origin remote, so Flatpak itself never updates it. The flatpak channel now fetches the release manifest, compares versions, and shows a non-installable 'View release' notification instead of staying silent. deb/rpm/MSI/NSIS keep the full self-install flow; package-manager installs (AUR) stay silent since their repo delivers updates. Independent review round 3: production_quality.

[juacker]

Added a persistent update indicator in the fleet top bar (2e8fba0), per feedback that a dismissible toast alone is too easy to miss:

• AppUpdateBadge: an "Update available · vX" pill next to the settings gear, visible until the update is applied. Click opens Settings → About (which hosts install / view-release controls). Covers both installable and notify-only (Flatpak) channels.
• useAvailableAppUpdate hook shared by badge and toast: seeds from get_app_update_status, follows app-updates://available; live events win over the seed.
• Toast dismissal is now version-keyed: dismissing v1 stays dismissed for v1, a later v2 re-surfaces it. Install error/progress state resets when a new version arrives.
• Manual checks now emit the update event too, so an update found via Settings → About surfaces the badge — the user is always aware, however the update was discovered.
• 4 new unit tests for the badge.

Validation: cargo fmt/clippy -D warnings, 829 lib tests, tsc, eslint, prettier, 183 vitest, vite build — all green. Independent review rounds 4+5: production_quality, no open findings.

[juacker]

Reworked the settings model per feedback (7ba055f):

• Checking for updates is now always on — no setting. It's a cheap anonymous manifest fetch; the user must at least learn an update exists (notify-only builds like Flatpak included).
• autoUpdate.enabled → autoUpdate.autoDownload (default on). When enabled on a self-update-capable build, the package is downloaded in the background after any check that finds one; the badge/toast flip to "Update ready — restart to apply" and install reuses the cached, signature-verified bytes.
• The Settings → About toggle ("Automatically download updates") only renders on builds that can self-update — no dead toggle on Flatpak/notify-only installs.

Validation: cargo clippy -D warnings, 834 backend tests (+5), tsc/eslint/prettier, 185 frontend tests (+2), vite build. Two independent review rounds on this commit: final verdict production_quality, 0 findings.

[juacker]

Fixed the ugly Updates panel on non-updatable builds (d542e51): dev builds and package-manager installs (e.g. AUR) were rendering the support reason twice (the backend mirrors it into lastCheck.error) plus a permanently disabled 'Check for updates' button. The panel now collapses to just title + reason + Unavailable badge for those builds. Flatpak (notify-only) and self-updating builds are unchanged. Added AboutSettings tests for both states. Reviewed: production_quality, 0 findings.

[juacker]

Per user decision (c9ee962, replaces d542e51): builds that can neither self-update nor check for updates (dev, package-manager installs like AUR) now render no Updates panel at all in Settings → About — not even the collapsed 'Unavailable' header. The panel also stays hidden until update support is known, so there's no appear-then-vanish flicker on load; it still appears if the status read itself fails, so errors stay visible. Flatpak (notify-only) and self-updating builds unchanged. Reviewed twice: production_quality, 0 findings.