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/fleet/api_deploy_deckies.py

@@ -3,6 +3,7 @@ import os
 from fastapi import APIRouter, Depends, HTTPException
 
 from decnet.logging import get_logger
+from decnet.telemetry import traced as _traced
 from decnet.config import DEFAULT_MUTATE_INTERVAL, DecnetConfig, _ROOT
 from decnet.engine import deploy as _deploy
 from decnet.ini_loader import load_ini_from_string
@@ -27,6 +28,7 @@ router = APIRouter()
         500: {"description": "Deployment failed"}
     }
 )
+@_traced("api.deploy_deckies")
 async def api_deploy_deckies(req: DeployIniRequest, admin: dict = Depends(require_admin)) -> dict[str, str]:
     from decnet.fleet import build_deckies_from_ini