v1.2.1 — Manifest fix

• Fixed missing data_collection_permissions declaration required by Mozilla's updated submission policy
• No functional changes from v1.2.0

Initial public release of SleepingTab.

What's new:
• Automatic sleeping of inactive tabs
• Lightweight tab activity monitoring
• Live activity graph
• Configurable auto-sleep timer
• Ignore pinned and audio-playing tabs
• Privacy-friendly design with no telemetry or tracking

This release focuses on lightweight performance, minimal resource usage, and a clean Firefox-native experience.