修复首次会话等待与上游饱和重试

tests/unit/opencode-error-details.test.ts

@@ -0,0 +1,21 @@
+import { describe, expect, it } from 'vitest';
+import { isOpencodeUpstreamSaturated } from '../../shared/opencode-error-details';
+
+describe('isOpencodeUpstreamSaturated', () => {
+  it.each([
+    '当前分组上游负载已饱和，请稍后再试',
+    JSON.stringify({ error: { message: 'UPSTREAM capacity is SATURATED; try later' } }),
+  ])('classifies explicit upstream saturation evidence: %s', (message) => {
+    expect(isOpencodeUpstreamSaturated(message)).toBe(true);
+  });
+
+  it.each([
+    'rate_limit_exceeded',
+    JSON.stringify({ error: { code: 'rate_limit_exceeded', message: 'Rate limit exceeded' } }),
+    'upstream request failed',
+    'provider saturated',
+    'user quota is not enough',
+  ])('does not broaden saturation classification to other retry failures: %s', (message) => {
+    expect(isOpencodeUpstreamSaturated(message)).toBe(false);
+  });
+});