Persist lookup data to disk and refresh on app foreground

- DataManager now persists lookup data (residence types, task categories,
  priorities, statuses, specialties, templates) to disk
- Loads cached lookups on app startup for faster launch
- iOS: Refresh lookups when app becomes active, refresh widget on background
- Android: Initialize DataManager in onCreate, already had onResume refresh
- Only send ETag if lookup data is actually in memory to avoid 304 with no data

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

composeApp/src/androidMain/kotlin/com/example/casera/MainActivity.kt

@@ -33,6 +33,8 @@ import com.example.casera.fcm.FCMManager
 import com.example.casera.platform.BillingManager
 import com.example.casera.network.APILayer
 import com.example.casera.sharing.ContractorSharingManager
+import com.example.casera.data.DataManager
+import com.example.casera.data.PersistenceManager
 import kotlinx.coroutines.launch
 
 class MainActivity : ComponentActivity(), SingletonImageLoader.Factory {
@@ -55,6 +57,14 @@ class MainActivity : ComponentActivity(), SingletonImageLoader.Factory {
         ThemeStorage.initialize(ThemeStorageManager.getInstance(applicationContext))
         ThemeManager.initialize()
 
+        // Initialize DataManager with platform-specific managers
+        // This loads cached lookup data from disk for faster startup
+        DataManager.initialize(
+            tokenMgr = TokenManager.getInstance(applicationContext),
+            themeMgr = ThemeStorageManager.getInstance(applicationContext),
+            persistenceMgr = PersistenceManager.getInstance(applicationContext)
+        )
+
         // Initialize BillingManager for subscription management
         billingManager = BillingManager.getInstance(applicationContext)