feat: GPS workout UI polish and voice guidance improvements

- Start native GPS service in paused state during pre-start (notification
  shows "Waiting to start..." instead of running timer)
- Bump notification importance to IMPORTANCE_DEFAULT for lock screen
- Theme-aware glass blur overlay matching header style (dark/light mode)
- Dark Nord blue background for activity picker, audio stats panel
- Transparent overlay in pre-start, gradient fade for cancel button
- Use Toggle component for voice announcements checkbox
- Persist voice guidance settings to localStorage
- Derive voice language from page language, remove language selector

src-tauri/gen/android/app/src/main/java/org/bocken/app/AndroidBridge.kt

@@ -19,7 +19,7 @@ class AndroidBridge(private val context: Context) {
     private var ttsForVoices: TextToSpeech? = null
 
     @JavascriptInterface
-    fun startLocationService(ttsConfigJson: String) {
+    fun startLocationService(ttsConfigJson: String, startPaused: Boolean) {
         if (context is Activity) {
             // Request notification permission on Android 13+ (required for foreground service notification)
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
@@ -50,6 +50,7 @@ class AndroidBridge(private val context: Context) {
 
         val intent = Intent(context, LocationForegroundService::class.java).apply {
             putExtra("ttsConfig", ttsConfigJson)
+            putExtra("startPaused", startPaused)
         }
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             context.startForegroundService(intent)
@@ -58,10 +59,16 @@ class AndroidBridge(private val context: Context) {
         }
     }
 
-    /** Backwards-compatible overload for calls without TTS config */
+    /** Overload: TTS config only (not paused) */
+    @JavascriptInterface
+    fun startLocationService(ttsConfigJson: String) {
+        startLocationService(ttsConfigJson, false)
+    }
+
+    /** Overload: no args (not paused, no TTS) */
     @JavascriptInterface
     fun startLocationService() {
-        startLocationService("{}")
+        startLocationService("{}", false)
     }
 
     @JavascriptInterface

src-tauri/gen/android/app/src/main/java/org/bocken/app/LocationForegroundService.kt

@@ -127,10 +127,11 @@ class LocationForegroundService : Service(), TextToSpeech.OnInitListener {
     }
 
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        val startPaused = intent?.getBooleanExtra("startPaused", false) ?: false
         startTimeMs = System.currentTimeMillis()
         pausedAccumulatedMs = 0L
-        pausedSinceMs = 0L
-        paused = false
+        pausedSinceMs = if (startPaused) startTimeMs else 0L
+        paused = startPaused
         totalDistanceKm = 0.0
         lastLat = Double.NaN
         lastLng = Double.NaN
@@ -151,7 +152,11 @@ class LocationForegroundService : Service(), TextToSpeech.OnInitListener {
             PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
         )
 
-        val notification = buildNotification("0:00", "0.00 km", "")
+        val notification = if (startPaused) {
+            buildNotification("Waiting to start...", "", "")
+        } else {
+            buildNotification("0:00", "0.00 km", "")
+        }
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
             startForeground(NOTIFICATION_ID, notification, android.content.pm.ServiceInfo.FOREGROUND_SERVICE_TYPE_LOCATION)
@@ -488,7 +493,7 @@ class LocationForegroundService : Service(), TextToSpeech.OnInitListener {
             val channel = NotificationChannel(
                 CHANNEL_ID,
                 "GPS Tracking",
-                NotificationManager.IMPORTANCE_LOW
+                NotificationManager.IMPORTANCE_DEFAULT
             ).apply {
                 description = "Shows while GPS is recording your workout"
             }