Fix: your sign-in now survives a browser restart.

• The extension asked you to click "Connect" on every browser start even though the Twitch authorization was still valid: the token was being discarded on shutdown. It is now kept, and the popup opens straight onto your channels. With no stored session, the "Connect with Twitch" screen appears as before.
• Notifications and the toolbar counter therefore work from startup, without having to open the popup first.
• Live channels are checked at startup, so the first notification no longer waits for two check intervals.
• An unreachable network at startup no longer signs you out. Only Twitch explicitly rejecting the token ends the session.