v1.0.18: fix ON_CHANGE never starting, improve version display

- Start FileWatchService from SyncFlowApp.onCreate() for any existing
  enabled ON_CHANGE pairs — previously the watcher only started on
  device boot or explicit pair toggle, so existing pairs after an
  app update never got watched
- About screen now shows "Version X.Y.Z (build N)" updating
  automatically from BuildConfig on every release

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

app/src/main/kotlin/com/syncflow/SyncFlowApp.kt

@@ -3,7 +3,13 @@ package com.syncflow
 import android.app.Application
 import androidx.hilt.work.HiltWorkerFactory
 import androidx.work.Configuration
+import com.syncflow.data.db.SyncPairDao
+import com.syncflow.domain.model.ScheduleType
+import com.syncflow.worker.FileWatchService
 import dagger.hilt.android.HiltAndroidApp
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
 import timber.log.Timber
 import javax.inject.Inject
 
@@ -11,10 +17,16 @@ import javax.inject.Inject
 class SyncFlowApp : Application(), Configuration.Provider {
 
     @Inject lateinit var workerFactory: HiltWorkerFactory
+    @Inject lateinit var syncPairDao: SyncPairDao
 
     override fun onCreate() {
         super.onCreate()
         if (BuildConfig.DEBUG) Timber.plant(Timber.DebugTree())
+        // Start file watcher on every app launch for any existing ON_CHANGE pairs
+        CoroutineScope(Dispatchers.IO).launch {
+            val hasOnChange = syncPairDao.getEnabled().any { it.scheduleType == ScheduleType.ON_CHANGE }
+            if (hasOnChange) FileWatchService.start(this@SyncFlowApp)
+        }
     }
 
     override val workManagerConfiguration: Configuration