docs: incident reports for send-task crash and playout ring desync

Two root-caused bugs documented with full evidence:

1. Send task fatal exit on QUIC congestion (FIXED in 2092245)
   - send_media() Err(Blocked) caused break → killed entire call
   - Now drops packet and continues

2. Playout ring buffer cursor desync (ROOT-CAUSED, fix pending)
   - AudioRing::write() mutates read_pos from producer thread on overflow
   - Violates SPSC contract → reader/writer fight over read_pos
   - Causes 12-16s bidirectional silence ~25-30s into call
   - Both clients affected simultaneously

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

Cargo.lock

@@ -43,6 +43,12 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "android_log-sys"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85965b6739a430150bdd138e2374a98af0c3ee0d030b3bb7fc3bddff58d0102e"
+
 [[package]]
 name = "android_system_properties"
 version = "0.1.5"
@@ -3180,6 +3186,17 @@ dependencies = [
  "tracing-core",
 ]
 
+[[package]]
+name = "tracing-android"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12612be8f868a09c0ceae7113ff26afe79d81a24473a393cb9120ece162e86c0"
+dependencies = [
+ "android_log-sys",
+ "tracing",
+ "tracing-subscriber",
+]
+
 [[package]]
 name = "tracing-attributes"
 version = "0.1.31"
@@ -4018,6 +4035,7 @@ dependencies = [
  "thiserror 2.0.18",
  "tokio",
  "tracing",
+ "tracing-android",
  "tracing-subscriber",
  "wzp-codec",
  "wzp-crypto",