feat: adaptive quality engine + codec indicator UI

Wire AdaptiveQualityController into Android engine for auto codec
switching based on network quality reports. Add color-coded TX/RX
codec badges to the in-call screen showing active codecs and Auto mode.

- Recv task: ingest QualityReports, feed to controller, signal profile
  changes via AtomicU8 to send task
- Send task: check for pending profile switch at frame boundaries,
  update encoder/FEC/frame size
- Track peer codec from incoming packet headers
- Kotlin UI: codec badges (blue=studio, green=good, amber=degraded,
  red=catastrophic) with Auto tag
- Add .taskmaster to .gitignore

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

android/app/src/main/java/com/wzp/engine/CallStats.kt

@@ -33,6 +33,12 @@ data class CallStats(
     val fecRecovered: Long = 0,
     /** Current mic audio level (RMS, 0-32767). */
     val audioLevel: Int = 0,
+    /** Our current outgoing codec (e.g. "Opus24k"). */
+    val currentCodec: String = "",
+    /** Last seen incoming codec from peers. */
+    val peerCodec: String = "",
+    /** Whether auto quality mode is active. */
+    val autoMode: Boolean = false,
     /** Number of participants in the room. */
     val roomParticipantCount: Int = 0,
     /** Participants in the room (fingerprint + optional alias). */
@@ -76,6 +82,9 @@ data class CallStats(
                     underruns = obj.optLong("underruns", 0),
                     fecRecovered = obj.optLong("fec_recovered", 0),
                     audioLevel = obj.optInt("audio_level", 0),
+                    currentCodec = obj.optString("current_codec", ""),
+                    peerCodec = obj.optString("peer_codec", ""),
+                    autoMode = obj.optBoolean("auto_mode", false),
                     roomParticipantCount = obj.optInt("room_participant_count", 0),
                     roomParticipants = parseParticipants(obj.optJSONArray("room_participants"))
                 )