refactor: Centralize Meshtastic intent constants

This commit centralizes all Android Intent constants into a new `MeshtasticIntent` object within the `core/api` module.

This refactoring makes the constants accessible to external applications and removes the duplicated definitions from the main application. The app and the service example have been updated to use these new centralized constants.

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

core/api/src/main/kotlin/org/meshtastic/core/api/MeshtasticIntent.kt

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2025-2026 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.api
+
+import org.meshtastic.core.api.MeshtasticIntent.EXTRA_CONNECTED
+import org.meshtastic.core.api.MeshtasticIntent.EXTRA_NODEINFO
+import org.meshtastic.core.api.MeshtasticIntent.EXTRA_PACKET_ID
+import org.meshtastic.core.api.MeshtasticIntent.EXTRA_STATUS
+
+
+/**
+ * Constants for Meshtastic Android Intents. These are used by external applications to communicate with the Meshtastic
+ * service.
+ */
+object MeshtasticIntent {
+    private const val PREFIX = "com.geeksville.mesh"
+
+    /** Broadcast when a node's information changes. Extra: [EXTRA_NODEINFO] */
+    const val ACTION_NODE_CHANGE = "$PREFIX.NODE_CHANGE"
+
+    /** Broadcast when the mesh radio connects. Extra: [EXTRA_CONNECTED] */
+    const val ACTION_MESH_CONNECTED = "$PREFIX.MESH_CONNECTED"
+
+    /** Broadcast when the mesh radio disconnects. */
+    const val ACTION_MESH_DISCONNECTED = "$PREFIX.MESH_DISCONNECTED"
+
+    /** Legacy broadcast for connection changes. Extra: [EXTRA_CONNECTED] */
+    const val ACTION_CONNECTION_CHANGED = "$PREFIX.CONNECTION_CHANGED"
+
+    /** Broadcast for message status updates. Extras: [EXTRA_PACKET_ID], [EXTRA_STATUS] */
+    const val ACTION_MESSAGE_STATUS = "$PREFIX.MESSAGE_STATUS"
+
+    /** Received a text message. */
+    const val ACTION_RECEIVED_TEXT_MESSAGE_APP = "$PREFIX.RECEIVED.TEXT_MESSAGE_APP"
+
+    /** Received a position update. */
+    const val ACTION_RECEIVED_POSITION_APP = "$PREFIX.RECEIVED.POSITION_APP"
+
+    /** Received node info. */
+    const val ACTION_RECEIVED_NODEINFO_APP = "$PREFIX.RECEIVED.NODEINFO_APP"
+
+    /** Received telemetry data. */
+    const val ACTION_RECEIVED_TELEMETRY_APP = "$PREFIX.RECEIVED.TELEMETRY_APP"
+
+    /** Received ATAK Plugin data. */
+    const val ACTION_RECEIVED_ATAK_PLUGIN = "$PREFIX.RECEIVED.ATAK_PLUGIN"
+
+    /** Received ATAK Forwarder data. */
+    const val ACTION_RECEIVED_ATAK_FORWARDER = "$PREFIX.RECEIVED.ATAK_FORWARDER"
+
+    /** Received detection sensor data. */
+    const val ACTION_RECEIVED_DETECTION_SENSOR_APP = "$PREFIX.RECEIVED.DETECTION_SENSOR_APP"
+
+    /** Received private app data. */
+    const val ACTION_RECEIVED_PRIVATE_APP = "$PREFIX.RECEIVED.PRIVATE_APP"
+
+    // standard EXTRA bundle definitions
+    const val EXTRA_CONNECTED = "$PREFIX.Connected"
+    const val EXTRA_PAYLOAD = "$PREFIX.Payload"
+    const val EXTRA_NODEINFO = "$PREFIX.NodeInfo"
+    const val EXTRA_PACKET_ID = "$PREFIX.PacketId"
+    const val EXTRA_STATUS = "$PREFIX.Status"
+}