feat: complete OTEL tracing across all services with pipeline bridge and docs

Extends tracing to every remaining module: all 23 API route handlers,
correlation engine, sniffer (fingerprint/p0f/syslog), prober (jarm/hassh/tcpfp),
profiler behavioral analysis, logging subsystem, engine, and mutator.

Bridges the ingester→SSE trace gap by persisting trace_id/span_id columns on
the logs table and creating OTEL span links in the SSE endpoint. Adds log-trace
correlation via _TraceContextFilter injecting otel_trace_id into Python LogRecords.

Includes development/docs/TRACING.md with full span reference (76 spans),
pipeline propagation architecture, quick start guide, and troubleshooting.

decnet/engine/deployer.py

@@ -68,6 +68,7 @@ _PERMANENT_ERRORS = (
 )
 
 
+@_traced("engine.compose_with_retry")
 def _compose_with_retry(
     *args: str,
     compose_file: Path = COMPOSE_FILE,