fix(runtime-fallback): match Volcano Engine 'exceeded the usage quota' errors

Volcano Engine sends quota exceeded errors with the words in reverse
order: 'You have exceeded the 5-hour usage quota'. The existing
patterns required 'quota' to precede 'exceeded', so they never matched.

- Add /exceeded.*quota/i and /usage.?quota/i to RETRYABLE_ERROR_PATTERNS
- Add exceeded.*quota and usage\s*quota to AUTO_RETRY_PATTERNS
- Add regression tests for both detection paths

Fixes: runtime-fallback not triggering on Volcano Engine quota errors

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

@@ -0,0 +1,41 @@
+import { describe, expect, test } from "bun:test"
+
+import { extractAutoRetrySignal } from "./auto-retry-signal"
+
+describe("extractAutoRetrySignal", () => {
+  test("detects Volcano Engine 'exceeded the usage quota' signal", () => {
+    //#given
+    const info = {
+      status: "You have exceeded the 5-hour usage quota. It will reset at 2026-05-11 01:20:12 +0800 CST.",
+    }
+
+    //#when
+    const signal = extractAutoRetrySignal(info)
+
+    //#then
+    expect(signal).toBeDefined()
+    expect(signal?.signal).toContain("exceeded")
+  })
+
+  test("detects standard 'quota exceeded' signal", () => {
+    //#given
+    const info = { message: "Quota exceeded for model gpt-4" }
+
+    //#when
+    const signal = extractAutoRetrySignal(info)
+
+    //#then
+    expect(signal).toBeDefined()
+  })
+
+  test("returns undefined for non-retryable info", () => {
+    //#given
+    const info = { message: "Something went wrong" }
+
+    //#when
+    const signal = extractAutoRetrySignal(info)
+
+    //#then
+    expect(signal).toBeUndefined()
+  })
+})