refactor(coordinator-api,blockchain-explorer): add response caching and fix timestamp handling

- Add cached decorator to admin stats, job status, payment status, and marketplace stats endpoints
- Configure cache TTLs using get_cache_config for different endpoint types (1min job_list, 30s user_balance, marketplace_stats)
- Import cache_management router and include it in main app with /v1 prefix
- Fix blockchain-explorer formatTimestamp to handle both ISO string and Unix numeric timestamps with type

apps/coordinator-api/src/app/main.py

@@ -25,7 +25,8 @@ from .routers import (
     explorer,
     payments,
     web_vitals,
-    edge_gpu
+    edge_gpu,
+    cache_management
 )
 from .routers.ml_zk_proofs import router as ml_zk_proofs
 from .routers.community import router as community_router
@@ -221,6 +222,7 @@ def create_app() -> FastAPI:
     app.include_router(openclaw_enhanced, prefix="/v1")
     app.include_router(monitoring_dashboard, prefix="/v1")
     app.include_router(multi_modal_rl_router, prefix="/v1")
+    app.include_router(cache_management, prefix="/v1")
 
     # Add Prometheus metrics endpoint
     metrics_app = make_asgi_app()