sync: keep microphone uplink freshness-first

AGENTS.md

@@ -175,5 +175,6 @@ Context: the mirrored browser probe finally reproduced the real failure class on
   - 0.16.22 live mirrored run still failed with p95 `433.7 ms`, median `-359.4 ms`, and 5 paired coded pulses. Client telemetry showed camera uplink `latest_age_ms` repeatedly around `300-350 ms`, matching the measured skew; patch 0.16.23 to make video queues latest-only instead of draining stale-but-under-budget backlog.
   - 0.16.23 local validation passed for fresh-queue behavior, uplink/probe freshness contracts, sync analyzer tests, client/server binary checks, and whitespace checks.
   - 0.16.23 live mirrored run improved to p95 `215.2 ms`, median `+142.2 ms`, 13 paired coded pulses, and raw activity alignment within `6.6 ms` of coded pairs. Patch 0.16.24 makes the probe print local client and remote server versions before capture so every run records what was actually tested.
+  - 0.16.24 live mirrored run improved again to p95 `168.4 ms`, median `-19.1 ms`, 11 paired coded pulses, but still failed because individual paired pulses bounced between about `-168 ms` and `+45 ms`. Client logs showed the microphone uplink queue still accumulating depth `16`; patch 0.16.25 makes microphone uplink queues latest-only too so stale audio PTS cannot continue acting as the server timing master under backpressure.
 - [ ] Re-run the mirrored browser probe after the pre-start false-positive fix.
 - [ ] Run Google Meet manual validation.

Cargo.lock

@@ -1652,7 +1652,7 @@ checksum = "09edd9e8b54e49e587e4f6295a7d29c3ea94d469cb40ab8ca70b288248a81db2"
 
 [[package]]
 name = "lesavka_client"
-version = "0.16.24"
+version = "0.16.25"
 dependencies = [
  "anyhow",
  "async-stream",
@@ -1686,7 +1686,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_common"
-version = "0.16.24"
+version = "0.16.25"
 dependencies = [
  "anyhow",
  "base64",
@@ -1698,7 +1698,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_server"
-version = "0.16.24"
+version = "0.16.25"
 dependencies = [
  "anyhow",
  "base64",

client/Cargo.toml

@@ -4,7 +4,7 @@ path                    = "src/main.rs"
 
 [package]
 name                    = "lesavka_client"
-version                 = "0.16.24"
+version                 = "0.16.25"
 edition                 = "2024"
 
 [dependencies]

client/src/app/uplink_media.rs

@@ -261,7 +261,7 @@ const AUDIO_UPLINK_QUEUE: crate::uplink_fresh_queue::FreshQueueConfig =
     crate::uplink_fresh_queue::FreshQueueConfig {
         capacity: 16,
         max_age: Duration::from_millis(400),
-        policy: crate::uplink_fresh_queue::FreshQueuePolicy::DrainOldest,
+        policy: crate::uplink_fresh_queue::FreshQueuePolicy::LatestOnly,
     };
 
 #[cfg(not(coverage))]

client/src/sync_probe/capture.rs

@@ -52,7 +52,7 @@ const PROBE_VIDEO_QUEUE: FreshQueueConfig = FreshQueueConfig {
 const PROBE_AUDIO_QUEUE: FreshQueueConfig = FreshQueueConfig {
     capacity: 32,
     max_age: Duration::from_millis(400),
-    policy: crate::uplink_fresh_queue::FreshQueuePolicy::DrainOldest,
+    policy: crate::uplink_fresh_queue::FreshQueuePolicy::LatestOnly,
 };
 
 #[cfg(any(not(coverage), test))]

common/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name                    = "lesavka_common"
-version                 = "0.16.24"
+version                 = "0.16.25"
 edition                 = "2024"
 build                   = "build.rs"
 

server/Cargo.toml

@@ -10,7 +10,7 @@ bench                   = false
 
 [package]
 name                    = "lesavka_server"
-version                 = "0.16.24"
+version                 = "0.16.25"
 edition                 = "2024"
 autobins                = false
 

testing/tests/client_uplink_freshness_contract.rs

@@ -82,7 +82,7 @@ fn microphone_uplink_queue_freshness_budget_stays_within_live_audio_window() {
         max_age_ms <= 400,
         "AUDIO_UPLINK_QUEUE max_age is {max_age_ms}ms; keep it <= 400ms for live calls"
     );
-    assert_queue_policy(block, "AUDIO_UPLINK_QUEUE", "DrainOldest");
+    assert_queue_policy(block, "AUDIO_UPLINK_QUEUE", "LatestOnly");
 }
 
 #[test]
@@ -105,3 +105,14 @@ fn sync_probe_video_queue_uses_same_freshness_budget() {
     );
     assert_queue_policy(block, "PROBE_VIDEO_QUEUE", "LatestOnly");
 }
+
+#[test]
+fn sync_probe_audio_queue_uses_live_latest_only_policy() {
+    let block = queue_block(SYNC_PROBE_CAPTURE_SRC, "PROBE_AUDIO_QUEUE");
+    let max_age_ms = parse_queue_max_age_ms(block, "PROBE_AUDIO_QUEUE");
+    assert!(
+        max_age_ms <= 400,
+        "PROBE_AUDIO_QUEUE max_age is {max_age_ms}ms; keep probe audio from preserving stale timing anchors"
+    );
+    assert_queue_policy(block, "PROBE_AUDIO_QUEUE", "LatestOnly");
+}