feat(app): wire file storage DI, cleanup worker, and integration tests

Add DI wiring with graceful MinIO fallback, background cleanup worker for expired sessions and leaked multipart uploads, and end-to-end integration tests.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

cmd/server/main_test.go

@@ -43,6 +43,7 @@ func TestRouterRegistration(t *testing.T) {
 		handler.NewJobHandler(jobSvc, zap.NewNop()),
 		handler.NewClusterHandler(service.NewClusterService(client, zap.NewNop()), zap.NewNop()),
 		appH,
+		nil, nil, nil,
 		nil,
 	)
 
@@ -103,6 +104,7 @@ func TestSmokeGetJobsEndpoint(t *testing.T) {
 		handler.NewJobHandler(jobSvc, zap.NewNop()),
 		handler.NewClusterHandler(service.NewClusterService(client, zap.NewNop()), zap.NewNop()),
 		appH,
+		nil, nil, nil,
 		nil,
 	)