Fix notification spam, stale frame count, and neighbor flicker

- Post the ongoing status on a fresh LOW channel (cellguard_status_v2) and
  delete the legacy channel, whose importance was stuck at HIGH (a channel's
  importance is immutable after creation) and heads-up'd on every 4s poll.
- Read the live capture total from the /proc/cgcap/frames header instead of
  the detector's snapshot, which could lag behind.
- Accumulate neighbor towers across polls with a 120s TTL instead of
  publishing the raw per-poll getAllCellInfo list, which blinked empty
  whenever a scan returned only the serving cell.

app/src/main/java/com/seteclabs/cellguard/service/DetectorService.kt

@@ -105,7 +105,8 @@ class DetectorService : Service() {
         val frameTowers = FrameDecoder.decodeFrames(framesText)
         val towers = if (fwTowers.isNotEmpty()) fwTowers else frameTowers
         val serving = towers.firstOrNull { it.registered } ?: towers.firstOrNull()
-        val neighbors = towers.filter { it !== serving && !it.registered }.distinct()
+        val currentNeighbors = towers.filter { it !== serving && !it.registered }.distinct()
+        val neighbors = mergeNeighbors(currentNeighbors, serving)
 
         val servingPlmn = status.plmn.takeIf { it.isNotBlank() && it != "?" }
             ?: FrameDecoder.firstPlmn(framesText)
@@ -128,7 +129,7 @@ class DetectorService : Service() {
             plmn = plmn,
             operator = operator,
             rat = rat,
-            frames = status.frames,
+            frames = parseTotal(framesText) ?: status.frames,
             blockEnabled = status.block,
             detectEnabled = status.detect,
             ratLock = status.ratLock,
@@ -137,6 +138,35 @@ class DetectorService : Service() {
         )
     }
 
+    private data class SeenTower(val tower: Tower, val lastSeen: Long)
+    private val neighborCache = LinkedHashMap<String, SeenTower>()
+
+    private fun towerKey(t: Tower): String =
+        "${t.rat}|${t.mcc}${t.mnc}|${t.ci}|${t.pci}|${t.earfcn}"
+
+    /**
+     * Neighbor towers arrive per-poll from getAllCellInfo(), which frequently
+     * reports only the serving cell on any given scan. Publishing the raw per-poll
+     * list makes the table blink empty every 4s. Instead accumulate seen neighbors
+     * keyed by identity and age them out after [NEIGHBOR_TTL_MS], so a tower stays
+     * listed (with its most recent signal) until it is genuinely gone.
+     */
+    private fun mergeNeighbors(current: List<Tower>, serving: Tower?): List<Tower> {
+        val now = System.currentTimeMillis()
+        current.forEach { neighborCache[towerKey(it)] = SeenTower(it, now) }
+        val servingKey = serving?.let { towerKey(it) }
+        neighborCache.entries.removeAll { (k, v) ->
+            k == servingKey || now - v.lastSeen > NEIGHBOR_TTL_MS
+        }
+        return neighborCache.values.sortedByDescending { it.lastSeen }.map { it.tower }
+    }
+
+    /** True live capture count from the `# total=N` header line of /proc/cgcap/frames. */
+    private fun parseTotal(framesText: String): Long? {
+        val line = framesText.lineSequence().firstOrNull { it.startsWith("# total=") } ?: return null
+        return Regex("total=(\\d+)").find(line)?.groupValues?.get(1)?.toLongOrNull()
+    }
+
     /** On-device heuristics merged with the shell detector's `suspect` token. */
     private fun buildSuspects(
         towers: List<Tower>,
@@ -192,6 +222,11 @@ class DetectorService : Service() {
 
     private fun createChannel() {
         val mgr = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+        // A channel's importance is immutable after creation. Earlier builds created
+        // "cellguard" at HIGH, so the ongoing status notification heads-up/sounds on
+        // every 4s poll (the reported spam). The only fix is to abandon that id:
+        // delete the legacy channel and post the silent status on a fresh LOW one.
+        runCatching { mgr.deleteNotificationChannel(LEGACY_CHANNEL_ID) }
         // Ongoing status: LOW importance -> silent, no heads-up, no per-poll spam.
         if (mgr.getNotificationChannel(CHANNEL_ID) == null) {
             mgr.createNotificationChannel(
@@ -315,11 +350,13 @@ class DetectorService : Service() {
             PackageManager.PERMISSION_GRANTED
 
     companion object {
-        const val CHANNEL_ID = "cellguard"
+        const val CHANNEL_ID = "cellguard_status_v2"
+        private const val LEGACY_CHANNEL_ID = "cellguard"
         const val ALERT_CHANNEL_ID = "cellguard_alert"
         private const val NOTIF_ID = 0x0C6D
         private const val ALERT_NOTIF_ID = 0x0C6E
         private const val POLL_MS = 4_000L
+        private const val NEIGHBOR_TTL_MS = 120_000L
 
         private val ALERT_FMT = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.US)