feat: Integrate notification management and preferences across platforms (#4819)

Signed-off-by: James Rich <2199651+jamesarich@users.noreply.github.com>

core/repository/src/commonMain/kotlin/org/meshtastic/core/repository/AppPreferences.kt

@@ -84,6 +84,21 @@ interface UiPrefs {
     fun setShouldProvideNodeLocation(nodeNum: Int, provide: Boolean)
 }
 
+/** Reactive interface for notification preferences. */
+interface NotificationPrefs {
+    val messagesEnabled: StateFlow<Boolean>
+
+    fun setMessagesEnabled(enabled: Boolean)
+
+    val nodeEventsEnabled: StateFlow<Boolean>
+
+    fun setNodeEventsEnabled(enabled: Boolean)
+
+    val lowBatteryEnabled: StateFlow<Boolean>
+
+    fun setLowBatteryEnabled(enabled: Boolean)
+}
+
 /** Reactive interface for general map preferences. */
 interface MapPrefs {
     val mapStyle: StateFlow<Int>

core/repository/src/commonMain/kotlin/org/meshtastic/core/repository/Notification.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2026 Meshtastic LLC
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.meshtastic.core.repository
+
+data class Notification(
+    val title: String,
+    val message: String,
+    val type: Type = Type.Info,
+    val category: Category = Category.Message,
+    val contactKey: String? = null,
+    val isSilent: Boolean = false,
+    val group: String? = null,
+    val id: Int? = null,
+) {
+    enum class Type {
+        None,
+        Info,
+        Warning,
+        Error,
+    }
+
+    enum class Category {
+        Message,
+        NodeEvent,
+        Battery,
+        Alert,
+        Service,
+    }
+}

core/repository/src/commonMain/kotlin/org/meshtastic/core/repository/NotificationManager.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2026 Meshtastic LLC
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.meshtastic.core.repository
+
+interface NotificationManager {
+    fun dispatch(notification: Notification)
+
+    fun cancel(id: Int)
+
+    fun cancelAll()
+}