fix(fdroid): Firebase-free stubs for expo-notifications

fdroid/expo-notifications-patches/service/delegates/FirebaseMessagingDelegate.kt

@@ -0,0 +1,54 @@
+package expo.modules.notifications.service.delegates
+
+import android.content.Context
+import android.os.Bundle
+import expo.modules.notifications.notifications.background.BackgroundRemoteNotificationTaskConsumer
+import expo.modules.notifications.tokens.interfaces.FirebaseTokenListener
+import java.lang.ref.WeakReference
+import java.util.*
+
+/**
+ * Stub implementation (Firebase-free) for F-Droid builds.
+ * This app only uses local notifications - no FCM push tokens or remote messages.
+ */
+open class FirebaseMessagingDelegate(protected val context: Context) :
+    expo.modules.notifications.service.interfaces.FirebaseMessagingDelegate {
+
+  companion object {
+    protected var sLastToken: String? = null
+    protected val sTokenListenersReferences = WeakHashMap<FirebaseTokenListener, WeakReference<FirebaseTokenListener?>?>()
+    protected var sBackgroundTaskConsumerReferences = WeakHashMap<BackgroundRemoteNotificationTaskConsumer, WeakReference<BackgroundRemoteNotificationTaskConsumer>>()
+
+    @JvmStatic
+    fun addTokenListener(listener: FirebaseTokenListener) {
+      if (!sTokenListenersReferences.containsKey(listener)) {
+        sTokenListenersReferences[listener] = WeakReference(listener)
+        sLastToken?.let { listener.onNewToken(it) }
+      }
+    }
+
+    fun addBackgroundTaskConsumer(taskConsumer: BackgroundRemoteNotificationTaskConsumer) {
+      if (!sBackgroundTaskConsumerReferences.containsKey(taskConsumer)) {
+        sBackgroundTaskConsumerReferences[taskConsumer] = WeakReference(taskConsumer)
+      }
+    }
+
+    fun getBackgroundTasks() = sBackgroundTaskConsumerReferences.values.mapNotNull { it.get() }
+
+    /** No-op for F-Droid builds (no FCM, local notifications only). */
+    fun runTaskManagerTasks(applicationContext: Context, bundle: Bundle) {
+      // no-op: no FCM in this build
+    }
+  }
+
+  override fun onNewToken(token: String) {
+    for (listenerReference in sTokenListenersReferences.values) {
+      listenerReference?.get()?.onNewToken(token)
+    }
+    sLastToken = token
+  }
+
+  override fun onDeletedMessages() {
+    // no-op
+  }
+}