Replace hardcoded platform values and appStore.platform with
Capacitor.getPlatform() for accurate runtime platform detection.
Changes:
- HomeView: Use Capacitor.getPlatform() instead of appStore.platform
- StatusView: Use Capacitor.getPlatform() for initial diagnostics
- diagnostics-export: Replace hardcoded 'Android' with Capacitor detection
- StatusView: Fix timezone to use actual timezone instead of 'Unknown'
- diagnostics-export: Show 'N/A' for API Level on iOS/web (Android-specific)
Fixes platform badge showing "web" on iOS native and diagnostics
showing incorrect platform information.