v1.0.16: spinning sync icon, colorful icon, ON_CHANGE fix, notification fix

- Sync icon now rotates (CSS-style spin) in StatusPill, StatusBanner,
  and card sync button whenever status is SYNCING
- Launcher icon redesigned: indigo→violet→cyan gradient background,
  upload arrow fades white→sky-blue, download arrow fades white→violet,
  soft glow ring behind arrows
- Fix ON_CHANGE not triggering: FileWatchService.start() now called
  from AddPairViewModel.save() so pairs created with ON_CHANGE
  immediately begin watching without needing a toggle or reboot
- Fix FileWatch notification hidden: IMPORTANCE_MIN → IMPORTANCE_LOW
  so the "Watching N folders" notification shows in the shade

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/src/main/kotlin/com/syncflow/ui/pairdetail/PairDetailScreen.kt

@@ -1,5 +1,10 @@
 package com.syncflow.ui.pairdetail
 
+import androidx.compose.animation.core.LinearEasing
+import androidx.compose.animation.core.animateFloat
+import androidx.compose.animation.core.infiniteRepeatable
+import androidx.compose.animation.core.rememberInfiniteTransition
+import androidx.compose.animation.core.tween
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
@@ -13,6 +18,7 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.graphicsLayer
 import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
 import com.syncflow.data.db.entities.SyncEventEntity
@@ -143,6 +149,11 @@ private fun StatusBanner(pair: SyncPairEntity) {
         SyncStatus.PARTIAL  -> Triple(Icons.Default.WarningAmber,"Partial",   MaterialTheme.colorScheme.tertiaryContainer)
         SyncStatus.IDLE     -> Triple(Icons.Outlined.Circle,     "Idle",      MaterialTheme.colorScheme.surfaceVariant)
     }
+    val rotation by rememberInfiniteTransition(label = "bannerSpin").animateFloat(
+        initialValue = 0f, targetValue = 360f,
+        animationSpec = infiniteRepeatable(tween(1000, easing = LinearEasing)),
+        label = "bannerRotation",
+    )
     Surface(
         color = containerColor,
         shape = RoundedCornerShape(16.dp),
@@ -152,7 +163,12 @@ private fun StatusBanner(pair: SyncPairEntity) {
             modifier = Modifier.padding(16.dp),
             verticalAlignment = Alignment.CenterVertically,
         ) {
-            Icon(icon, null, modifier = Modifier.size(40.dp))
+            Icon(
+                icon, null,
+                modifier = Modifier.size(40.dp).graphicsLayer {
+                    if (pair.lastSyncResult == SyncStatus.SYNCING) rotationZ = rotation
+                },
+            )
             Spacer(Modifier.width(16.dp))
             Column {
                 Text(label, style = MaterialTheme.typography.titleMedium)