feat: add optimistic locking and improve type safety

- Implement optimistic locking for deposit balance updates
  - Prevent race conditions in concurrent deposit requests
  - Add automatic retry with exponential backoff (max 3 attempts)
  - Add version column to user_deposits table

- Improve type safety across codebase
  - Add explicit types for Namecheap API responses
  - Add typed function arguments (ManageDepositArgs, etc.)
  - Remove `any` types from deposit-agent and tool files

- Add reconciliation job for balance integrity verification
  - Compare user_deposits.balance vs SUM(confirmed transactions)
  - Alert admin on discrepancy detection

- Set up test environment with Vitest + Miniflare
  - Add 50+ test cases for deposit system
  - Add helper functions for test data creation

- Update documentation
  - Add migration guide for version columns
  - Document optimistic locking patterns

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/services/conversation-service.ts

@@ -1,4 +1,4 @@
-import { Env } from '../types';
+import type { Env, KeyboardData } from '../types';
 import {
   addToBuffer,
   processAndSummarize,
@@ -9,7 +9,7 @@ import { sendChatAction } from '../telegram';
 export interface ConversationResult {
   responseText: string;
   isProfileUpdated: boolean;
-  keyboardData?: any;
+  keyboardData?: KeyboardData | null;
 }
 
 export class ConversationService {
@@ -53,13 +53,13 @@ export class ConversationService {
     );
 
     // 키보드 데이터 파싱
-    let keyboardData: any = null;
+    let keyboardData: KeyboardData | null = null;
     const keyboardMatch = responseText.match(/__KEYBOARD__(.+?)__END__\n?/);
-    
+
     if (keyboardMatch) {
       responseText = responseText.replace(/__KEYBOARD__.+?__END__\n?/, '');
       try {
-        keyboardData = JSON.parse(keyboardMatch[1]);
+        keyboardData = JSON.parse(keyboardMatch[1]) as KeyboardData;
       } catch (e) {
         console.error('[ConversationService] Keyboard parsing error:', e);
       }