fix: mic aware shared device detection, mute persistence, feedback tooltips

[kibermaks]

Description

Three targeted fixes: Mic Aware false triggers on shared audio devices, mute state not persisting across restarts, and missing feedback rating tooltips.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code refactoring
• Performance improvement
• Build/CI change

Changes Made

• Mic Aware shared device detection — MicrophoneMonitor now detects when the default input and output devices are the same hardware (e.g. Thunderbolt Display). When detected, Mic Aware is bypassed in applyMuteState() and the Settings toggle is disabled with a warning explaining why and how to fix it.
• Mute persistence fix — AwarenessMuteButton was only toggling audioService.muteEnabled without syncing back to awarenessService.config.muteEnabled, so the state was never saved to UserDefaults. Now it updates both.
• Feedback rating tooltips — Added .help() labels to rating icons in timeline event blocks, ProductivityCard, and MonthlyStatsView so users can see what each emoji means on hover.
• Feedback rating toggle-off — Clicking an already-selected rating now clears it instead of being a no-op.

Testing Checklist

• App builds without errors or warnings
• All existing features still work
• Mute toggle persists after app restart
• Mic Aware warning appears when input/output share a device
• Feedback rating tooltips show on hover
• Clicking an active rating clears it

Checklist

• My code follows the project's coding standards
• I have tested my changes thoroughly
• My changes generate no new warnings