refactor: replace SessionDep with explicit Annotated[Session, Depends(get_session)] across all routers

- Replace SessionDep type alias with explicit Annotated[Session, Depends(get_session)]
- Add missing imports for Session and Annotated types
- Update all endpoint function signatures to use explicit dependency annotation
- Apply changes consistently across all router files (admin, agent, marketplace, etc.)
- Add marketplace_gpu router to main.py router includes

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

@@ -251,6 +251,10 @@ def create_app() -> FastAPI:
     app.include_router(payments, prefix="/v1")
     app.include_router(web_vitals, prefix="/v1")
     app.include_router(edge_gpu)
+    
+    # Add standalone routers for tasks and payments
+    app.include_router(marketplace_gpu, prefix="/v1")
+    
     if ml_zk_proofs:
         app.include_router(ml_zk_proofs)
     app.include_router(marketplace_enhanced, prefix="/v1")