fix(runtime-fallback): also classify Volcano Engine errors as quota_exceeded

- Add /exceeded.*quota/i and /usage\s*quota/i to classifyErrorType quota block
- Align /usage.?quota/i -> /usage\s*quota/i in RETRYABLE_ERROR_PATTERNS for consistency
- Strengthen auto-retry-signal test assertion
- Add classifyErrorType assertion to Volcano Engine regression test

Ensures Volcano Engine errors are both retryable AND logged as
errorType: quota_exceeded.

src/hooks/runtime-fallback/auto-retry-signal.test.ts

@@ -15,6 +15,7 @@ describe("extractAutoRetrySignal", () => {
     //#then
     expect(signal).toBeDefined()
     expect(signal?.signal).toContain("exceeded")
+    expect(signal?.signal).toContain("usage quota")
   })
 
   test("detects standard 'quota exceeded' signal", () => {