Add signed GitHub auto-updater

[StephanOrgiazzi]

Summary

• add the official Tauri updater plugin and check GitHub Releases on normal app startup
• prompt with Install / Later when a newer release is available
• keep autostart launches silent (no update prompt at Windows login)
• generate signed updater artifacts and latest.json from a Windows GitHub Actions release workflow
• document the one-time Tauri updater signing-key setup

Release setup required

Before the first updater-enabled release, configure:

• repository secret TAURI_SIGNING_PRIVATE_KEY
• optional repository secret TAURI_SIGNING_PRIVATE_KEY_PASSWORD
• repository variable TAURI_UPDATER_PUBLIC_KEY

See docs/releasing.md for the signer command and release flow.

Notes

• release builds use the NSIS updater path; Tauri's Windows updater defaults to passive installation, allowing the per-machine installer to request elevation
• the existing NSIS hooks continue to stop/remove and recreate the private Everything service during upgrades
• local builds without TAURI_UPDATER_PUBLIC_KEY compile normally and simply skip update checks

Validation

• Cargo.lock was regenerated from the existing master lockfile without unrelated dependency upgrades
• scripts/check.ps1 passes on a clean Windows GitHub Actions runner with the updater integration enabled

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Check for updates when an autostart instance is opened

After the app registers itself for autostart, the normal post-login state is a long-lived --autostart instance, so this condition skips its only update check. A later interactive launch is handled by the single-instance callback above, which only shows the existing window and never calls check_on_start; consequently, users who leave the tray process running will never be offered updates after reboot. Trigger the check when a non-autostart secondary launch opens the existing instance (with suitable deduplication), while keeping the initial login launch silent.

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