feat: JWT auth, user management, audit logging system

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/main.py

@@ -4,6 +4,8 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from app.database import engine, Base
+from app.api import auth, users, audit
+from app.middleware.audit import AuditMiddleware
 
 
 @asynccontextmanager
@@ -27,6 +29,11 @@ app.add_middleware(
     allow_methods=["*"],
     allow_headers=["*"],
 )
+app.add_middleware(AuditMiddleware)
+
+app.include_router(auth.router)
+app.include_router(users.router)
+app.include_router(audit.router)
 
 
 @app.get("/api/v1/health")