Fix WebSocketDisconnect tracebacks and handle closed receives gracefully

Fix VAD queue corruption, ASR duplicate calls, and LLM TTFT bottlenecks

Optimize TTFT, add connection pooling, implement streaming ASR with stabilization and waterfall metrics

Refine Stage 2: Add MemoryService, JSON logging middleware, and fuzzed stress tests

Deploy Stage 2 decoupled Event-Driven Conversational Runtime architecture