v0.6.3

Improvements

• Upgrade pairing token generation to use a 32-byte cryptographically secure random sequence.
• Migrate pairing token storage from UserDefaults to KeychainCredentialStore for enhanced security.
• Redesign the "Connect Browser Extension" settings pane to be browser-agnostic with links to both Firefox and Chrome extension stores.
• Add a "Regenerate" button to instantly invalidate and recreate the pairing token.

Fixes

• Fix CORS preflight failures for the new /ping extension connection check by allowing GET methods in the local server.