Initial implementation of Telegram AI customer support bot

Cloudflare Workers + Hono + D1 + KV + R2 stack with 4 specialized AI agents
(onboarding, troubleshoot, asset, billing), OpenAI function calling with
7 tool definitions, human escalation, pending action approval workflow,
feedback collection, audit logging, i18n (ko/en), and Workers AI fallback.

43 source files, 45 tests passing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/utils/retry.test.ts

@@ -0,0 +1,66 @@
+import { describe, it, expect } from 'vitest';
+import { retryWithBackoff, RetryError } from '../../src/utils/retry';
+
+describe('retryWithBackoff', () => {
+  it('succeeds on first attempt without retrying', async () => {
+    let callCount = 0;
+    const result = await retryWithBackoff(async () => {
+      callCount++;
+      return 'ok';
+    }, { maxRetries: 3, initialDelayMs: 1, jitter: false });
+
+    expect(result).toBe('ok');
+    expect(callCount).toBe(1);
+  });
+
+  it('retries and succeeds on 2nd attempt', async () => {
+    let callCount = 0;
+    const result = await retryWithBackoff(async () => {
+      callCount++;
+      if (callCount < 2) throw new Error('transient');
+      return 'recovered';
+    }, { maxRetries: 3, initialDelayMs: 1, jitter: false });
+
+    expect(result).toBe('recovered');
+    expect(callCount).toBe(2);
+  });
+
+  it('throws RetryError after all attempts exhausted', async () => {
+    let callCount = 0;
+    await expect(
+      retryWithBackoff(async () => {
+        callCount++;
+        throw new Error('permanent');
+      }, { maxRetries: 2, initialDelayMs: 1, jitter: false })
+    ).rejects.toThrow(RetryError);
+
+    // 1 initial + 2 retries = 3 total
+    expect(callCount).toBe(3);
+  });
+
+  it('respects maxRetries option', async () => {
+    let callCount = 0;
+    await expect(
+      retryWithBackoff(async () => {
+        callCount++;
+        throw new Error('fail');
+      }, { maxRetries: 1, initialDelayMs: 1, jitter: false })
+    ).rejects.toThrow(RetryError);
+
+    // 1 initial + 1 retry = 2 total
+    expect(callCount).toBe(2);
+  });
+
+  it('RetryError contains attempt count and last error', async () => {
+    try {
+      await retryWithBackoff(async () => {
+        throw new Error('specific failure');
+      }, { maxRetries: 2, initialDelayMs: 1, jitter: false });
+    } catch (error) {
+      expect(error).toBeInstanceOf(RetryError);
+      const retryErr = error as RetryError;
+      expect(retryErr.attempts).toBe(3);
+      expect(retryErr.lastError.message).toBe('specific failure');
+    }
+  });
+});