v1.2.0 — Dual Timer System + Security Fixes

New Features:
- Hardcore Mode: 24/7 block for days/weeks. For serious addictions.
- Focus Mode (Short Timer): Block for hours during work sessions. Auto-unlocks when time expires.
- Both modes run independently with separate passwords and domain lists.
- Focus Mode supports YouTube allowlist and schedule hours.
- Blocked page now shows correct context (hardcore vs focus session).

Fixes:
- Google, GitHub, Mozilla and other auth/login domains are now permanently exempt from blocking — no more getting locked out of sign-in flows.
- Fixed Firefox redirect compatibility issue with blocking rules.
- Added keyword blocking support to Focus Mode.
- Removed unsafe innerHTML usage throughout.