log_requests middleware (BaseHTTPMiddleware) showed no-trace
because anyio.create_task_group() in Starlette 0.50.0 does not
always propagate ContextVar from raw ASGI TraceContextMiddleware.
Fix 1: defensive get_trace_id() check at log_requests entry —
if empty, seed_trace_id() to ensure every request has one.
Fix 2: CotJsonFormatter used 'if error:' and 'if payload:' which
silently drop empty strings (str(e)='') and empty dicts.
Changed to 'is not None' checks — preserves all data.
Root cause: 12 EXPLORE-without-error entries from belief_scope's
exception handler where Exception() has empty message.
busya
60674c8639