[daily] route codex websocket through site api endpoints (#386)

* fix: route codex websocket through site api endpoints

* fix: preserve websocket endpoint exhaustion errors

* test: align proxy route mocks with first-byte timeout helpers

src/server/proxy-core/surfaces/sharedSurface.test.ts

@@ -384,6 +384,8 @@ describe('selectSurfaceChannelForAttempt', () => {
       modelActual: 'upstream-model',
       status: 'failed',
       httpStatus: 502,
+      isStream: null,
+      firstByteLatencyMs: null,
       latencyMs: 1200,
       promptTokens: 10,
       completionTokens: 5,
@@ -995,6 +997,8 @@ describe('selectSurfaceChannelForAttempt', () => {
       modelRequested: 'gpt-5.2',
       status: 'success',
       httpStatus: 200,
+      isStream: null,
+      firstByteLatencyMs: null,
       latencyMs: 250,
       errorMessage: null,
       retryCount: 1,