[Feature] Add manual alarm button as GPS fallback

[mattekudacy]

Description

Add a manual "Wake Me Up" button that users can press if GPS fails or if they want to trigger the alarm manually.

Problem

• GPS can sometimes fail or lose signal
• Users might be in a tunnel or area with poor reception
• Current app relies entirely on GPS for notifications

Proposed Solution

Add a prominent button on the tracking screen:

┌─────────────────────────────┐
│                                                                            │
│ [🔔 WAKE ME UP NOW]                                    │
│                                                                            │
│ Tap if GPS isn't working                                     │
│ or you want to wake up                                     │
└─────────────────────────────┘

## Behavior
- Triggers the same alarm/notification as auto-detection
- Vibration + sound + persistent notification
- Button always visible during tracking

## Acceptance Criteria
- [ ] Manual alarm button on tracking screen
- [ ] Same notification behavior as auto-detection
- [ ] Works even when GPS is unavailable
- [ ] Visual feedback when pressed