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"))
                 )

android/app/src/main/java/com/wzp/ui/call/InCallScreen.kt

@@ -463,7 +463,51 @@ fun InCallScreen(
 
                 Spacer(modifier = Modifier.height(12.dp))
 
-                // Stats
+                // Codec + Stats
+                if (stats.currentCodec.isNotEmpty()) {
+                    val codecLabel = formatCodecName(stats.currentCodec)
+                    val peerLabel = if (stats.peerCodec.isNotEmpty()) formatCodecName(stats.peerCodec) else null
+                    val autoTag = if (stats.autoMode) " [Auto]" else ""
+                    Row(
+                        modifier = Modifier.fillMaxWidth(),
+                        horizontalArrangement = Arrangement.Center,
+                        verticalAlignment = Alignment.CenterVertically
+                    ) {
+                        // Our codec badge
+                        Surface(
+                            shape = RoundedCornerShape(4.dp),
+                            color = codecColor(stats.currentCodec)
+                        ) {
+                            Text(
+                                text = "TX $codecLabel$autoTag",
+                                modifier = Modifier.padding(horizontal = 6.dp, vertical = 2.dp),
+                                style = MaterialTheme.typography.labelSmall.copy(
+                                    fontFamily = FontFamily.Monospace,
+                                    fontSize = 10.sp
+                                ),
+                                color = Color.White
+                            )
+                        }
+                        if (peerLabel != null) {
+                            Spacer(modifier = Modifier.width(6.dp))
+                            Surface(
+                                shape = RoundedCornerShape(4.dp),
+                                color = codecColor(stats.peerCodec)
+                            ) {
+                                Text(
+                                    text = "RX $peerLabel",
+                                    modifier = Modifier.padding(horizontal = 6.dp, vertical = 2.dp),
+                                    style = MaterialTheme.typography.labelSmall.copy(
+                                        fontFamily = FontFamily.Monospace,
+                                        fontSize = 10.sp
+                                    ),
+                                    color = Color.White
+                                )
+                            }
+                        }
+                    }
+                    Spacer(modifier = Modifier.height(4.dp))
+                }
                 Text(
                     text = "TX: ${stats.framesEncoded} | RX: ${stats.framesDecoded}",
                     style = MaterialTheme.typography.labelSmall.copy(fontFamily = FontFamily.Monospace),
@@ -825,3 +869,25 @@ private fun DebugReportCard(
         }
     }
 }
+
+/** Map Rust CodecId debug name to a human-readable label. */
+private fun formatCodecName(codecId: String): String = when (codecId) {
+    "Opus64k" -> "Opus 64k"
+    "Opus48k" -> "Opus 48k"
+    "Opus32k" -> "Opus 32k"
+    "Opus24k" -> "Opus 24k"
+    "Opus16k" -> "Opus 16k"
+    "Opus6k" -> "Opus 6k"
+    "Codec2_3200" -> "C2 3.2k"
+    "Codec2_1200" -> "C2 1.2k"
+    else -> codecId
+}
+
+/** Color-code codec badges by quality tier. */
+private fun codecColor(codecId: String): Color = when (codecId) {
+    "Opus64k", "Opus48k", "Opus32k" -> Color(0xFF0D6EFD) // blue — studio
+    "Opus24k", "Opus16k" -> Color(0xFF198754) // green — good
+    "Opus6k" -> Color(0xFFCC8800) // amber — degraded
+    "Codec2_3200", "Codec2_1200" -> Color(0xFFDC3545) // red — catastrophic
+    else -> Color(0xFF6C757D) // gray
+}