feat: foreground service, dB gain sliders, speaker routing, live network stats

- Wire CallService foreground service for background calls (microphone type)
- Add Voice Volume + Mic Gain sliders (-20 to +20 dB) applied in Kotlin
- Connect AudioRouteManager for real speaker toggle via AudioManager
- Feed quinn QUIC RTT into PathMonitor, display Loss/RTT/Jitter from live data
- Nuclear teardown between calls — recreate engine + audio pipeline each call
- Fix re-entrant teardown loop from CallService notification callback
- Park audio threads as daemons to avoid libcrypto TLS destructor crash on exit
- Remove duplicate wakelocks from Activity (service owns them now)
- Strip AEC + denoise from capture path, keep AGC only (incremental approach)
- Fix .so copy target: libwzp_android.so not libwzp.so

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

crates/wzp-transport/src/path_monitor.rs

@@ -136,6 +136,11 @@ impl PathMonitor {
         }
     }
 
+    /// Get raw packet counts for debugging.
+    pub fn counts(&self) -> (u64, u64) {
+        (self.total_sent, self.total_received)
+    }
+
     /// Estimate bandwidth in kbps from bytes received over time.
     fn estimate_bandwidth_kbps(&self) -> u32 {
         if let (Some(first), Some(last)) = (self.first_recv_time_ms, self.last_recv_time_ms) {