fix nests demoted speakers stuck on stage and broadcasting

Three related bugs when a host removes a speaker from the stage on
nostrnests by editing the kind-30312 to drop their p-tag:

1. NestRoomFilterAssembler didn't subscribe to the kind-30312 itself
   while in-room — only chat/presence/reactions (#a) and admin
   commands. Once joined, the room event was frozen on whatever
   version loaded the screen, so demotions never propagated. Added
   a per-relay filter on `kinds=[30312], authors=[host], #d=[dTag]`.

2. Even if the demotion did propagate, `BroadcastHandle` kept
   running. Only the manual Leave Stage button called
   `stopBroadcast()`. Added a LaunchedEffect that tears down the
   broadcast when the local user falls off `participantGrid.onStage`
   while still publishing — covers both demote-by-host and
   leave-stage-on-another-client.

3. The auto-stop reliably exercised a pre-existing
   NestForegroundService bug: when `startListening` was called to
   demote from mic+media to media-only, `intent.action == null`
   fell through to `else -> promoted`, keeping mic=true. The service
   then asked startForeground for FOREGROUND_SERVICE_TYPE_MICROPHONE
   after the mic had been released, threw SecurityException on
   Android 14+, runCatching swallowed it, stopSelf ran without
   startForeground → ForegroundServiceDidNotStartInTimeException.
   The explicit-demote branch now returns false; only intent==null
   (OS sticky-restart) preserves the prior promoted state.

amethyst/src/main/java/com/vitorpamplona/amethyst/service/nests/NestForegroundService.kt

@@ -310,10 +310,27 @@ class NestForegroundService : Service() {
         // startForegroundService MUST call startForeground within 5 s, on
         // every invocation (audit Android #8). Even the STOP path needs a
         // foreground state before stopForeground can demote it cleanly.
+        //
+        // Three startForegroundService entry points reach this code:
+        //   - `startListening(context)`  → intent != null, action == null
+        //     The wrapper is in listener-only mode; the service must
+        //     foreground with MEDIA_PLAYBACK type (no MICROPHONE).
+        //   - `promoteToMicrophone(ctx)` → intent.action == ACTION_PROMOTE_TO_MIC
+        //   - OS-restart of a START_STICKY service → intent == null
+        //     Preserve whatever foreground type we last ran with.
+        //
+        // The explicit demote branch (`else -> false`) is load-bearing:
+        // when the user leaves the stage, `startListening` is called to
+        // demote, AudioRecord is being released, and asking the OS for
+        // FOREGROUND_SERVICE_TYPE_MICROPHONE here throws SecurityException
+        // on Android 14+. The runCatching below would then `stopSelf()`
+        // without ever calling `startForeground`, tripping
+        // ForegroundServiceDidNotStartInTimeException.
         val mic =
-            when (intent?.action) {
-                ACTION_PROMOTE_TO_MIC -> true
-                else -> promoted
+            when {
+                intent == null -> promoted
+                intent.action == ACTION_PROMOTE_TO_MIC -> true
+                else -> false
             }
         runCatching { startForegroundWithType(includeMic = mic) }
             .onFailure {

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/nests/datasource/NestRoomFilterAssembler.kt

@@ -108,6 +108,25 @@ class NestRoomFilterSubAssembler(
                             since = since?.get(relay)?.time,
                         ),
                 ),
+                // Live-update subscription for the room event itself.
+                // EventFinder loads it once when missing and stops; the
+                // discovery-side feeds (FilterLiveActivitiesBy*) don't
+                // run while the user is inside a room. So without this
+                // third filter, a kind-30312 edit on the host's end
+                // (remove-from-stage, role change, status flip) never
+                // reaches the in-room screen — the demoted speaker
+                // keeps seeing themselves on stage and broadcasting,
+                // because participantGrid is built from a frozen event.
+                RelayBasedFilter(
+                    relay = relay,
+                    filter =
+                        Filter(
+                            kinds = listOf(MeetingSpaceEvent.KIND),
+                            authors = listOf(key.note.address.pubKeyHex),
+                            tags = mapOf("d" to listOf(key.note.address.dTag)),
+                            since = since?.get(relay)?.time,
+                        ),
+                ),
             )
         }
     }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/nests/room/activity/NestActivityContent.kt

@@ -33,6 +33,7 @@ import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -45,6 +46,7 @@ import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.commons.model.AddressableNote
+import com.vitorpamplona.amethyst.commons.viewmodels.BroadcastUiState
 import com.vitorpamplona.amethyst.commons.viewmodels.ConnectionUiState
 import com.vitorpamplona.amethyst.commons.viewmodels.NestViewModel
 import com.vitorpamplona.amethyst.commons.viewmodels.buildParticipantGrid
@@ -255,9 +257,31 @@ private fun NestActivityBody(
         remember(participantGrid) {
             participantGrid.onStage.map { it.pubkey }.toSet()
         }
+    val isOnStageMe = remember(onStageKeys, localPubkey) { localPubkey in onStageKeys }
 
     AutoConnectAndTrackSpeakers(viewModel, onStageKeys)
 
+    // Auto-stop broadcast if the local user falls off the stage while
+    // still publishing — covers two cases the manual Leave Stage button
+    // doesn't:
+    //   1. Host edits the kind-30312 to remove our `p`-tag (demotion).
+    //      Without this effect, the broadcast keeps running until the
+    //      user navigates away and the MoQ relay accepts the packets,
+    //      so a demoted speaker can keep talking on nostrnests.
+    //   2. The user taps Leave Stage on another client. Their kind-10312
+    //      arrives with onstage=0, participantGrid drops them, we tear
+    //      down here in mirror.
+    // Driven by participantGrid + presence (the same source as the
+    // StageGrid render), so it stays consistent with what the UI shows.
+    LaunchedEffect(isOnStageMe, ui.broadcast) {
+        if (!isOnStageMe &&
+            (ui.broadcast is BroadcastUiState.Broadcasting || ui.broadcast == BroadcastUiState.Connecting)
+        ) {
+            viewModel.stopBroadcast()
+            viewModel.setOnStage(false)
+        }
+    }
+
     // Single REQ per relay covering chat, presence, reactions, admin
     // commands. See NestRoomFilterAssembler for the filter shape.
     NestRoomFilterAssemblerSubscription(roomNote, accountViewModel)