feat: adaptive quality in desktop, relay quality directive, Oboe state polling

- Wire AdaptiveQualityController into desktop engine send/recv tasks
  (mirrors Android pattern: AtomicU8 pending_profile, auto-mode check)
- Wire same into Android engine send task (was only in recv before)
- QualityDirective SignalMessage variant for relay-initiated codec switch
- ParticipantQuality tracking in relay RoomManager (per-participant
  AdaptiveQualityController, weakest-link tier computation)
- Relay broadcasts QualityDirective to all participants when room-wide
  tier degrades (coordinated codec switching)
- Oboe stream state polling: poll getState() for up to 2s after
  requestStart() to ensure both streams reach Started before proceeding
  (fixes intermittent silent calls on cold start, Nothing Phone A059)

Tasks: #7, #25, #26, #31, #35

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

crates/wzp-native/cpp/oboe_bridge.cpp

@@ -8,6 +8,8 @@
 #include <android/log.h>
 #include <cstring>
 #include <atomic>
+#include <chrono>
+#include <thread>
 
 #define LOG_TAG "wzp-oboe"
 #define LOGI(...) __android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__)
@@ -388,6 +390,38 @@ int wzp_oboe_start(const WzpOboeConfig* config, const WzpOboeRings* rings) {
         return -5;
     }
 
+    // Log initial stream states right after requestStart() returns.
+    // On well-behaved HALs both will already be Started; on others
+    // (Nothing A059) they may still be in Starting state.
+    LOGI("requestStart returned: capture_state=%d playout_state=%d",
+         (int)g_capture_stream->getState(),
+         (int)g_playout_stream->getState());
+
+    // Poll until both streams report Started state, up to 2s timeout.
+    // Some Android HALs (Nothing A059) delay transitioning from Starting
+    // to Started; proceeding before the transition completes causes the
+    // first capture/playout callbacks to be dropped silently.
+    {
+        auto deadline = std::chrono::steady_clock::now() + std::chrono::milliseconds(2000);
+        int poll_count = 0;
+        while (std::chrono::steady_clock::now() < deadline) {
+            auto cap_state = g_capture_stream->getState();
+            auto play_state = g_playout_stream->getState();
+            if (cap_state == oboe::StreamState::Started &&
+                play_state == oboe::StreamState::Started) {
+                LOGI("both streams Started after %d polls", poll_count);
+                break;
+            }
+            poll_count++;
+            std::this_thread::sleep_for(std::chrono::milliseconds(10));
+        }
+        // Log final state even on timeout (helps diagnose HAL quirks)
+        LOGI("stream states after poll: capture=%d playout=%d (polls=%d)",
+             (int)g_capture_stream->getState(),
+             (int)g_playout_stream->getState(),
+             poll_count);
+    }
+
     LOGI("Oboe started: sr=%d burst=%d ch=%d",
          config->sample_rate, config->frames_per_burst, config->channel_count);
     return 0;