beacon: stop causing "wireless debugging connected" notification spam

Root cause of the spam the user kept seeing: the service resolved adbd's
own mDNS advertisement repeatedly (every discovery callback, plus a 20s
heartbeat). Resolving that service makes adbd re-arm the connection, and
Android posts a "wireless debugging connected" notification each time —
so the beacon itself was the noise source, independent of the PC-side
connector loops.

Now: resolve each discovered service instance exactly ONCE (guard set,
cleared on onServiceLost so a genuine rotation re-resolves once), and the
heartbeat only re-POSTs the cached port (60s, no mDNS traffic).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

echolot-app/adb-beacon/src/main/kotlin/app/echo_lot/adbbeacon/BeaconService.kt

@@ -38,6 +38,8 @@ class BeaconService : Service() {
     private var discoveryListener: NsdManager.DiscoveryListener? = null
 
     @Volatile private var currentPort: Int = -1
+    /** Service instances already resolved — prevents repeat resolves (notification spam). */
+    private val resolvedOnce = java.util.Collections.synchronizedSet(mutableSetOf<String>())
     private var heartbeat: Job? = null
 
     override fun onBind(intent: Intent?): IBinder? = null
@@ -47,10 +49,14 @@ class BeaconService : Service() {
         nsd = getSystemService(Context.NSD_SERVICE) as NsdManager
         startForeground(1, buildNotification("Starting…"))
         startDiscovery()
+        // Re-assert the endpoint periodically, but do NOT re-resolve mDNS each time:
+        // resolving adbd's own advertisement provokes it to re-arm the connection, which fires
+        // Android's "wireless debugging connected" notification — every cycle. Discovery runs
+        // once; we only re-POST the cached port (cheap, silent).
         heartbeat = scope.launch {
             while (true) {
-                report() // refresh seen_at + re-assert current endpoint
-                delay(20_000)
+                delay(60_000)
+                report()
             }
         }
         Status.set("watching for wireless-debug port…")
@@ -65,12 +71,18 @@ class BeaconService : Service() {
             override fun onServiceLost(s: NsdServiceInfo?) {
                 // adbd stops advertising when Wireless debugging is turned off.
                 currentPort = -1
+                s?.serviceName?.let { resolvedOnce.remove(it) } // allow one re-resolve when it returns
                 val warn = "⚠ Wireless debugging appears OFF (adb mDNS service gone) — re-enable it"
                 Status.set(warn)
                 updateNotification(warn)
             }
             override fun onServiceFound(s: NsdServiceInfo?) {
                 if (s == null) return
+                // Resolve ONCE per discovered service instance. Repeatedly resolving adbd's own
+                // advertisement makes it re-arm the connection and spam the user with
+                // "wireless debugging connected" notifications.
+                val key = s.serviceName ?: return
+                if (!resolvedOnce.add(key)) return
                 resolve(s)
             }
         }