logs: migrate to molecular CoT JSON protocol, fix regressions

- Replace BeliefFormatter with CotJsonFormatter (single-line JSON with
  ts, level, trace_id, src, marker, intent, payload, error, span_id)
- Migrate belief_scope to use cot_log() for structured JSON output
- Update monkey-patched reason/reflect/explore to pass extra= dict
- Strip 200+ inline [REASON]/[REFLECT]/[EXPLORE] markers from 50+ files
- Remove belief_scope from hot-path utilities (_parse_datetime,
  _json_load_if_needed) to eliminate startup log noise
- Register TraceContextMiddleware in app.py (was implemented but unused)
- Seed trace_id in startup_event/shutdown_event for background tasks
- Fix broken relative imports in translate routes (3 dots → 4 dots)
- Migrate 43 translate_routes log calls to logger.reason/explore
- Fix SyntaxError (positional arg after extra=) in _repo_operations_routes
- Fix IndentationError in rbac_permission_catalog except-block
- Add smoke test tests/test_smoke_app.py (catches import errors before run)

backend/src/api/routes/migration.py

@@ -357,8 +357,9 @@ async def trigger_sync_now(
                     credentials_id=env.id,  # Use env.id as credentials reference
                 )
                 db.add(db_env)
-                logger.info(
-                    f"[trigger_sync_now][REASON] Created environment row for {env.id}"
+                logger.reason(
+                    f"Created environment row for {env.id}",
+                    extra={"src": "trigger_sync_now"},
                 )
             else:
                 existing.name = env.name
@@ -373,7 +374,7 @@ async def trigger_sync_now(
                 client = SupersetClient(env)
                 service.sync_environment(env.id, client)
                 results["synced"].append(env.id)
-                logger.info(f"[trigger_sync_now][REASON] Synced environment {env.id}")
+                logger.reason(f"Synced environment {env.id}", extra={"src": "trigger_sync_now"})
             except Exception as e:
                 results["failed"].append({"env_id": env.id, "error": str(e)})
                 logger.error(f"[trigger_sync_now][Error] Failed to sync {env.id}: {e}")