feat: improved AEC, keyboard shortcuts, dedup participants, dev-fast profile

AEC improvements:
- Reduce echo tail from 100ms to 30ms (3.3x faster, suited for laptops)
- Add double-talk detection: freeze adaptation when near-end speaks
- Add residual echo suppression
- Disable AEC by default in --android mode (macOS has built-in AEC)

CLI features:
- Keyboard shortcuts: m=mic mute, s=speaker mute, q=quit (raw terminal mode)
- Dedup participants in RoomUpdate display (same fingerprint+alias shown once)
- Add dev-fast profile (opt-level 2 with incremental compilation)

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

crates/wzp-client/src/call.rs

@@ -241,7 +241,7 @@ impl CallEncoder {
             block_id: 0,
             frame_in_block: 0,
             timestamp_ms: 0,
-            aec: EchoCanceller::new(48000, 100), // 100 ms echo tail
+            aec: EchoCanceller::new(48000, 30), // 30ms echo tail (laptop/phone)
             agc: AutoGainControl::new(),
             silence_detector: SilenceDetector::new(
                 config.silence_threshold_rms,