feat: protocol improvements — live trunking, mini-frames, noise suppression, adaptive jitter

T6 wiring: Trunking in relay hot path
- TrunkedForwarder wraps transport with TrunkBatcher
- run_participant uses 5ms flush timer when trunking enabled
- send_trunk/recv_trunk on QuinnTransport
- --trunking flag on relay config
- 2 new tests: forwarder batches, auto-flush on full

T7 wiring: Mini-frames in encoder/decoder
- MediaPacket::encode_compact/decode_compact with MiniFrameContext
- CallEncoder sends mini-headers for consecutive frames (full every 50th)
- CallDecoder auto-detects full vs mini on receive
- mini_frames_enabled in CallConfig (default true)
- 3 new tests: encode/decode sequence, periodic full, disabled mode

Noise suppression (nnnoiseless/RNNoise)
- NoiseSupressor in wzp-codec: pure Rust ML-based noise removal
- Processes 960-sample frames as two 480-sample halves
- Integrated in CallEncoder before silence detection
- noise_suppression in CallConfig (default true)
- 4 new tests: creation, processing, SNR improvement, passthrough

T1-S4: Adaptive playout delay
- AdaptivePlayoutDelay: EMA-based jitter tracking (NetEq-inspired)
- Computes target_delay from observed inter-arrival jitter
- JitterBuffer::new_adaptive() uses adaptive delay
- adaptive_jitter in CallConfig (default true)
- 5 new tests: stable, jitter increase, recovery, clamping, estimate

272 tests passing across all crates.

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

crates/wzp-relay/src/config.rs

@@ -33,6 +33,12 @@ pub struct RelayConfig {
     /// Discovery is manual via multiple --probe flags; this flag signals intent.
     #[serde(default)]
     pub probe_mesh: bool,
+    /// Enable trunk batching for outgoing media in room mode.
+    /// When true, packets destined for the same receiver are accumulated into
+    /// [`TrunkFrame`]s and flushed every 5 ms (or when the batcher is full),
+    /// reducing per-packet QUIC datagram overhead.
+    #[serde(default)]
+    pub trunking_enabled: bool,
 }
 
 impl Default for RelayConfig {
@@ -48,6 +54,7 @@ impl Default for RelayConfig {
             metrics_port: None,
             probe_targets: Vec::new(),
             probe_mesh: false,
+            trunking_enabled: false,
         }
     }
 }