feat(audio-rooms): subscribeCatalog on NestsListener (moq-lite only)

Surface moq-lite's `catalog.json` track on the NestsListener API.
The catalog publishes one JSON object per group describing the
broadcast (codec, sample rate, optional speaker-side hints) and
is the canonical channel a watcher reads first to discover
available tracks.

Wire-up:
  * NestsListener.subscribeCatalog(pubkey) — interface method with
    a default body that throws UnsupportedOperationException, so
    the IETF DefaultNestsListener fails loud rather than returning
    a flow that never delivers data.
  * MoqLiteNestsListener overrides it to wrap
    `session.subscribe(broadcast = pubkey, track = "catalog.json")`
    through the same MoqObject mapping the audio path uses.
  * ReconnectingNestsListener routes both subscribeSpeaker and
    subscribeCatalog through a shared `reissuingSubscribe` helper —
    catalog handles also survive session swaps via the
    MutableSharedFlow re-issuance pump.

Tests:
  * NestsListenerCatalogTest — verifies the interface default
    rejects with UnsupportedOperationException so a caller wired
    against the IETF reference path fails fast.

VM/UI consumers (e.g. "speaker codec" tooltip) are intentionally
out of scope for this commit; this exposes the capability so a
follow-up can plug in a JSON parser + per-pubkey catalog cache.

nestsClient/src/commonTest/kotlin/com/vitorpamplona/nestsclient/NestsListenerCatalogTest.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.nestsclient
+
+import com.vitorpamplona.nestsclient.moq.SubscribeHandle
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertFailsWith
+
+class NestsListenerCatalogTest {
+    private class IetfStyleListener : NestsListener {
+        override val state: StateFlow<NestsListenerState> =
+            MutableStateFlow<NestsListenerState>(NestsListenerState.Idle).asStateFlow()
+
+        override suspend fun subscribeSpeaker(speakerPubkeyHex: String): SubscribeHandle = throw UnsupportedOperationException("not under test")
+
+        // Intentionally does NOT override subscribeCatalog so the
+        // interface's default body fires.
+
+        override suspend fun close() = Unit
+    }
+
+    @Test
+    fun ietfDefaultListenerRejectsCatalogSubscribe() =
+        runTest {
+            // The catalog channel is moq-lite only; the IETF listener
+            // path doesn't define one, so the interface default throws
+            // UnsupportedOperationException rather than silently
+            // returning a subscription that will never deliver data.
+            val listener = IetfStyleListener()
+            assertFailsWith<UnsupportedOperationException> {
+                listener.subscribeCatalog("speakerPubkey")
+            }
+        }
+}