fix(v1.5.0): Silent-Sync Mode + UI Improvements

Silent-Sync Implementation (Auto-Sync Banner Fix):
- Add SYNCING_SILENT state to SyncStateManager for background syncs
- Auto-sync (onResume) now triggers silently without banner interruption
- Silent-sync state blocks additional manual syncs (mutual exclusion)
- Error banners still display even after silent-sync failures
- SyncStatus tracks 'silent' flag to hide COMPLETED banners after silent-sync

UI/UX Improvements (from v1.5.0 post-migration fixes):
- Fix text wrapping in checklist items (singleLine=false, maxLines=5)
- Fix cursor position in text notes (use TextFieldValue with TextRange)
- Display app icon instead of emoji in AboutScreen
- Add smooth slide animations for NoteEditor transitions
- Remove visual noise from AboutScreen icon

Technical Changes:
- ComposeNoteEditorActivity: Add back animation with OnBackPressedCallback
- ComposeMainActivity: Add entry/exit slide animations for note editing
- NoteEditorScreen: Use TextFieldValue for proper cursor positioning
- ChecklistItemRow: Enable text wrapping for long checklist items
- AboutScreen: Convert Drawable to Bitmap via Canvas (supports AdaptiveIcon)
- SyncStatusBanner: Exclude SYNCING_SILENT from visibility checks
- MainActivity: Update legacy auto-sync to use silent mode

Fixes #[auto-sync-banner], improves #[user-experience]

Branch: feature/v1.5.0

android/app/src/main/java/dev/dettmer/simplenotes/MainActivity.kt

@@ -182,6 +182,11 @@ class MainActivity : AppCompatActivity() {
                     swipeRefreshLayout.isRefreshing = false
                     syncStatusBanner.visibility = View.GONE
                 }
+                // v1.5.0: Silent-Sync - Banner nicht anzeigen, aber Sync-Controls deaktivieren
+                SyncStateManager.SyncState.SYNCING_SILENT -> {
+                    setSyncControlsEnabled(false)
+                    // Kein Banner anzeigen bei Silent-Sync (z.B. onResume Auto-Sync)
+                }
             }
         }
     }
@@ -222,6 +227,7 @@ class MainActivity : AppCompatActivity() {
      * - Nur Success-Toast (kein "Auto-Sync..." Toast)
      * 
      * NOTE: WiFi-Connect Sync nutzt WorkManager (auch wenn App geschlossen!)
+     * v1.5.0: Silent-Sync - kein Banner während des Syncs, Fehler werden trotzdem angezeigt
      */
     private fun triggerAutoSync(source: String = "unknown") {
         // Throttling: Max 1 Sync pro Minute
@@ -230,7 +236,8 @@ class MainActivity : AppCompatActivity() {
         }
         
         // 🔄 v1.3.1: Check if sync already running
-        if (!SyncStateManager.tryStartSync("auto-$source")) {
+        // v1.5.0: silent=true - kein Banner bei Auto-Sync
+        if (!SyncStateManager.tryStartSync("auto-$source", silent = true)) {
             Logger.d(TAG, "⏭️ Auto-sync ($source): Another sync already in progress")
             return
         }

android/app/src/main/java/dev/dettmer/simplenotes/sync/SyncStateManager.kt

@@ -19,7 +19,8 @@ object SyncStateManager {
      */
     enum class SyncState {
         IDLE,           // Kein Sync aktiv
-        SYNCING,        // Sync läuft gerade
+        SYNCING,        // Sync läuft gerade (Banner sichtbar)
+        SYNCING_SILENT, // v1.5.0: Sync läuft im Hintergrund (kein Banner, z.B. onResume)
         COMPLETED,      // Sync erfolgreich abgeschlossen (kurz anzeigen)
         ERROR           // Sync fehlgeschlagen (kurz anzeigen)
     }
@@ -31,6 +32,7 @@ object SyncStateManager {
         val state: SyncState = SyncState.IDLE,
         val message: String? = null,
         val source: String? = null,  // "manual", "auto", "pullToRefresh", "background"
+        val silent: Boolean = false, // v1.5.0: Wenn true, wird nach Completion kein Banner angezeigt
         val timestamp: Long = System.currentTimeMillis()
     )
     
@@ -44,28 +46,35 @@ object SyncStateManager {
     private val lock = Any()
     
     /**
-     * Prüft ob gerade ein Sync läuft
+     * Prüft ob gerade ein Sync läuft (inkl. Silent-Sync)
      */
     val isSyncing: Boolean
-        get() = _syncStatus.value?.state == SyncState.SYNCING
+        get() {
+            val state = _syncStatus.value?.state
+            return state == SyncState.SYNCING || state == SyncState.SYNCING_SILENT
+        }
     
     /**
      * Versucht einen Sync zu starten.
+     * @param source Quelle des Syncs (für Logging)
+     * @param silent v1.5.0: Wenn true, wird kein Banner angezeigt (z.B. bei onResume Auto-Sync)
      * @return true wenn Sync gestartet werden kann, false wenn bereits einer läuft
      */
-    fun tryStartSync(source: String): Boolean {
+    fun tryStartSync(source: String, silent: Boolean = false): Boolean {
         synchronized(lock) {
             if (isSyncing) {
                 Logger.d(TAG, "⚠️ Sync already in progress, rejecting new sync from: $source")
                 return false
             }
             
-            Logger.d(TAG, "🔄 Starting sync from: $source")
+            val syncState = if (silent) SyncState.SYNCING_SILENT else SyncState.SYNCING
+            Logger.d(TAG, "🔄 Starting sync from: $source (silent=$silent)")
             _syncStatus.postValue(
                 SyncStatus(
-                    state = SyncState.SYNCING,
+                    state = syncState,
                     message = "Synchronisiere...",
-                    source = source
+                    source = source,
+                    silent = silent  // v1.5.0: Merkt sich ob silent für markCompleted()
                 )
             )
             return true
@@ -74,11 +83,21 @@ object SyncStateManager {
     
     /**
      * Markiert Sync als erfolgreich abgeschlossen
+     * v1.5.0: Bei Silent-Sync direkt auf IDLE wechseln (kein Banner)
      */
     fun markCompleted(message: String? = null) {
         synchronized(lock) {
-            val currentSource = _syncStatus.value?.source
+            val current = _syncStatus.value
-            Logger.d(TAG, "✅ Sync completed from: $currentSource")
+            val currentSource = current?.source
+            val wasSilent = current?.silent == true
+            
+            Logger.d(TAG, "✅ Sync completed from: $currentSource (silent=$wasSilent)")
+            
+            if (wasSilent) {
+                // v1.5.0: Silent-Sync - direkt auf IDLE, kein Banner anzeigen
+                _syncStatus.postValue(SyncStatus())
+            } else {
+                // Normaler Sync - COMPLETED State anzeigen
                 _syncStatus.postValue(
                     SyncStatus(
                         state = SyncState.COMPLETED,
@@ -88,6 +107,7 @@ object SyncStateManager {
                 )
             }
         }
+    }
     
     /**
      * Markiert Sync als fehlgeschlagen

android/app/src/main/java/dev/dettmer/simplenotes/ui/editor/ComposeNoteEditorActivity.kt

@@ -2,6 +2,7 @@ package dev.dettmer.simplenotes.ui.editor
 
 import android.os.Bundle
 import androidx.activity.ComponentActivity
+import androidx.activity.OnBackPressedCallback
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.activity.viewModels
@@ -48,11 +49,30 @@ class ComposeNoteEditorActivity : ComponentActivity() {
         
         enableEdgeToEdge()
         
+        // v1.5.0: Handle back button with slide animation
+        onBackPressedDispatcher.addCallback(this, object : OnBackPressedCallback(true) {
+            override fun handleOnBackPressed() {
+                finish()
+                @Suppress("DEPRECATION")
+                overridePendingTransition(
+                    dev.dettmer.simplenotes.R.anim.slide_in_left,
+                    dev.dettmer.simplenotes.R.anim.slide_out_right
+                )
+            }
+        })
+        
         setContent {
             SimpleNotesTheme {
                 NoteEditorScreen(
                     viewModel = viewModel,
-                    onNavigateBack = { finish() }
+                    onNavigateBack = {
+                        finish()
+                        @Suppress("DEPRECATION")
+                        overridePendingTransition(
+                            dev.dettmer.simplenotes.R.anim.slide_in_left,
+                            dev.dettmer.simplenotes.R.anim.slide_out_right
+                        )
+                    }
                 )
             }
         }

android/app/src/main/java/dev/dettmer/simplenotes/ui/editor/NoteEditorScreen.kt

@@ -13,6 +13,7 @@ import androidx.compose.foundation.layout.imePadding
 import androidx.compose.foundation.layout.offset
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.text.BasicTextField
 import androidx.compose.foundation.lazy.itemsIndexed
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.foundation.shape.RoundedCornerShape
@@ -43,6 +44,8 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.shadow
 import androidx.compose.ui.focus.FocusRequester
+import androidx.compose.ui.text.TextRange
+import androidx.compose.ui.text.input.TextFieldValue
 import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalSoftwareKeyboardController
@@ -252,9 +255,30 @@ private fun TextNoteContent(
     focusRequester: FocusRequester,
     modifier: Modifier = Modifier
 ) {
+    // v1.5.0: Use TextFieldValue to control cursor position
+    var textFieldValue by remember(content) {
+        mutableStateOf(TextFieldValue(
+            text = content,
+            selection = TextRange(content.length)
+        ))
+    }
+    
+    // Sync external changes
+    LaunchedEffect(content) {
+        if (textFieldValue.text != content) {
+            textFieldValue = TextFieldValue(
+                text = content,
+                selection = TextRange(content.length)
+            )
+        }
+    }
+    
     OutlinedTextField(
-        value = content,
+        value = textFieldValue,
-        onValueChange = onContentChange,
+        onValueChange = { newValue ->
+            textFieldValue = newValue
+            onContentChange(newValue.text)
+        },
         modifier = modifier.focusRequester(focusRequester),
         label = { Text(stringResource(R.string.content)) },
         shape = RoundedCornerShape(16.dp)

android/app/src/main/java/dev/dettmer/simplenotes/ui/editor/components/ChecklistItemRow.kt

@@ -142,7 +142,8 @@ fun ChecklistItemRow(
             keyboardActions = KeyboardActions(
                 onNext = { onAddNewItem() }
             ),
-            singleLine = true,
+            singleLine = false,
+            maxLines = 5,
             cursorBrush = SolidColor(MaterialTheme.colorScheme.primary),
             decorationBox = { innerTextField ->
                 Box {

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/ComposeMainActivity.kt

@@ -234,14 +234,28 @@ class ComposeMainActivity : ComponentActivity() {
         noteId?.let {
             intent.putExtra(ComposeNoteEditorActivity.EXTRA_NOTE_ID, it)
         }
-        startActivity(intent)
+        
+        // v1.5.0: Add slide animation
+        val options = ActivityOptions.makeCustomAnimation(
+            this,
+            dev.dettmer.simplenotes.R.anim.slide_in_right,
+            dev.dettmer.simplenotes.R.anim.slide_out_left
+        )
+        startActivity(intent, options.toBundle())
     }
     
     private fun createNote(noteType: NoteType) {
         cameFromEditor = true
         val intent = Intent(this, ComposeNoteEditorActivity::class.java)
         intent.putExtra(ComposeNoteEditorActivity.EXTRA_NOTE_TYPE, noteType.name)
-        startActivity(intent)
+        
+        // v1.5.0: Add slide animation
+        val options = ActivityOptions.makeCustomAnimation(
+            this,
+            dev.dettmer.simplenotes.R.anim.slide_in_right,
+            dev.dettmer.simplenotes.R.anim.slide_out_left
+        )
+        startActivity(intent, options.toBundle())
     }
     
     private fun openSettings() {

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/MainViewModel.kt

@@ -470,6 +470,7 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
     /**
      * Trigger auto-sync (onResume)
      * Only runs if server is configured and interval has passed
+     * v1.5.0: Silent-Sync - kein Banner während des Syncs, Fehler werden trotzdem angezeigt
      */
     fun triggerAutoSync(source: String = "auto") {
         // Throttling check
@@ -483,7 +484,8 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
             return
         }
         
-        if (!SyncStateManager.tryStartSync("auto-$source")) {
+        // v1.5.0: silent=true - kein Banner bei Auto-Sync, aber Fehler werden trotzdem angezeigt
+        if (!SyncStateManager.tryStartSync("auto-$source", silent = true)) {
             Logger.d(TAG, "⏭️ Auto-sync ($source): Another sync already in progress")
             return
         }

android/app/src/main/java/dev/dettmer/simplenotes/ui/main/components/SyncStatusBanner.kt

@@ -22,6 +22,7 @@ import dev.dettmer.simplenotes.sync.SyncStateManager
 /**
  * Sync status banner shown below the toolbar during sync
  * v1.5.0: Jetpack Compose MainActivity Redesign
+ * v1.5.0: SYNCING_SILENT ignorieren - Banner nur bei manuellen Syncs oder Fehlern anzeigen
  */
 @Composable
 fun SyncStatusBanner(
@@ -29,7 +30,10 @@ fun SyncStatusBanner(
     message: String?,
     modifier: Modifier = Modifier
 ) {
+    // v1.5.0: Banner nicht anzeigen bei IDLE oder SYNCING_SILENT (Auto-Sync im Hintergrund)
+    // Fehler werden trotzdem angezeigt (ERROR state nach Silent-Sync wechselt zu ERROR, nicht SYNCING_SILENT)
     val isVisible = syncState != SyncStateManager.SyncState.IDLE 
+                    && syncState != SyncStateManager.SyncState.SYNCING_SILENT
     
     AnimatedVisibility(
         visible = isVisible,
@@ -57,6 +61,7 @@ fun SyncStatusBanner(
             Text(
                 text = when (syncState) {
                     SyncStateManager.SyncState.SYNCING -> "Synchronisiere..."
+                    SyncStateManager.SyncState.SYNCING_SILENT -> "" // v1.5.0: Wird nicht angezeigt (isVisible = false)
                     SyncStateManager.SyncState.COMPLETED -> message ?: "Synchronisiert"
                     SyncStateManager.SyncState.ERROR -> message ?: "Fehler"
                     SyncStateManager.SyncState.IDLE -> ""

android/app/src/main/java/dev/dettmer/simplenotes/ui/settings/screens/AboutScreen.kt

@@ -1,8 +1,13 @@
 package dev.dettmer.simplenotes.ui.settings.screens
 
 import android.content.Intent
+import android.graphics.Bitmap
+import android.graphics.Canvas
 import android.net.Uri
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
@@ -13,6 +18,7 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.KeyboardArrowRight
@@ -25,11 +31,14 @@ import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
 import dev.dettmer.simplenotes.BuildConfig
 import dev.dettmer.simplenotes.ui.settings.components.SettingsDivider
 import dev.dettmer.simplenotes.ui.settings.components.SettingsScaffold
@@ -76,9 +85,26 @@ fun AboutScreen(
                         .padding(24.dp),
                     horizontalAlignment = Alignment.CenterHorizontally
                 ) {
-                    Text(
+                    // v1.5.0: App icon loaded from PackageManager and converted to Bitmap
-                        text = "📝",
+                    val context = LocalContext.current
-                        style = MaterialTheme.typography.displayMedium
+                    val appIcon = remember {
+                        val drawable = context.packageManager.getApplicationIcon(context.packageName)
+                        // Convert any Drawable (including AdaptiveIconDrawable) to Bitmap
+                        val bitmap = Bitmap.createBitmap(
+                            drawable.intrinsicWidth.coerceAtLeast(1),
+                            drawable.intrinsicHeight.coerceAtLeast(1),
+                            Bitmap.Config.ARGB_8888
+                        )
+                        val canvas = Canvas(bitmap)
+                        drawable.setBounds(0, 0, canvas.width, canvas.height)
+                        drawable.draw(canvas)
+                        bitmap.asImageBitmap()
+                    }
+                    
+                    Image(
+                        bitmap = appIcon,
+                        contentDescription = "App Icon",
+                        modifier = Modifier.size(96.dp)
                     )
                     
                     Spacer(modifier = Modifier.height(8.dp))