Electric SQL sync, Linear integration, and required updates

Electric SQL Sync #511

• Added task management UI with create, edit, and status tracking capabilities
• Implemented organization switching and multi-organization support
• Introduced local-first synchronization for tasks data via Electric SQL
• Bidirectional task updates that sync back to Linear via API

Linear Integration #503

• Added Linear integration with OAuth-based connection flow
• New integrations management page to connect and configure third-party services
• Task synchronization between Linear and local system with priority and team configuration
• Real-time sync from Linear via webhook

Required Updates #552

• Desktop app enforces a minimum required version via a remote endpoint
• New "Update Required" screen guides blocked users to check, download, or install updates
• App exposes its current version to the UI so version comparisons are accurate
• Fail-open behavior when API is unreachable, re-checks when network comes back online

Confirm on Quit #524

• Added a "Behavior" section in Settings with a "Confirm before quitting" toggle (defaults to enabled)
• App now shows a quit confirmation dialog when enabled and respects the toggle across restarts
• Update/install flows and programmatic quits can skip the confirmation to avoid blocking updates