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/web/router/config/api_get_config.py

@@ -1,6 +1,7 @@
 from fastapi import APIRouter, Depends
 
 from decnet.env import DECNET_DEVELOPER
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 from decnet.web.db.models import UserResponse
 
@@ -17,6 +18,7 @@ _DEFAULT_MUTATION_INTERVAL = "30m"
         401: {"description": "Could not validate credentials"},
     },
 )
+@_traced("api.get_config")
 async def api_get_config(user: dict = Depends(require_viewer)) -> dict:
     limits_state = await repo.get_state("config_limits")
     globals_state = await repo.get_state("config_globals")