refactor: migrate troubleshoot-agent from KV to D1

- Create troubleshoot_sessions table in D1
- Replace KV session storage with D1
- Unify field names to snake_case (user_id, collected_info, created_at, updated_at, expires_at)
- Add __PASSTHROUGH__/__SESSION_END__ marker support
- Change handler signature to match domain/deposit pattern
- Extract system prompt to constant TROUBLESHOOT_EXPERT_PROMPT
- Add hasTroubleshootSession() for routing
- Update openai-service.ts to use new D1-based functions
- Update troubleshoot-tool.ts to use D1 instead of KV
- Add TroubleshootSessionStatus type

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

src/openai-service.ts

@@ -7,7 +7,7 @@ import { metrics } from './utils/metrics';
 import { getOpenAIUrl } from './utils/api-urls';
 import { ERROR_MESSAGES } from './constants/messages';
 import { getServerSession, processServerConsultation } from './agents/server-agent';
-import { getTroubleshootSession, processTroubleshoot } from './agents/troubleshoot-agent';
+import { processTroubleshootConsultation, hasTroubleshootSession } from './agents/troubleshoot-agent';
 import { processDomainConsultation, hasDomainSession } from './agents/domain-agent';
 import { processDepositConsultation, hasDepositSession } from './agents/deposit-agent';
 import { sendMessage } from './telegram';
@@ -246,18 +246,17 @@ export async function generateOpenAIResponse(
 
     // Check if troubleshoot session is active
     try {
-      const troubleshootSession = await getTroubleshootSession(env.SESSION_KV, telegramUserId);
+      const hasTroubleshootSess = await hasTroubleshootSession(env.DB, telegramUserId);
 
-      if (troubleshootSession && troubleshootSession.status !== 'completed') {
-        logger.info('Active troubleshoot session detected, routing to troubleshoot', {
-          userId: telegramUserId,
-          status: troubleshootSession.status
+      if (hasTroubleshootSess) {
+        logger.info('트러블슈팅 세션 감지, 트러블슈팅 에이전트로 라우팅', {
+          userId: telegramUserId
         });
-        const result = await processTroubleshoot(userMessage, troubleshootSession, env);
+        const troubleshootResponse = await processTroubleshootConsultation(env.DB, telegramUserId, userMessage, env);
 
         // PASSTHROUGH: 무관한 메시지는 일반 처리로 전환
-        if (result !== '__PASSTHROUGH__') {
-          return result;
+        if (troubleshootResponse !== '__PASSTHROUGH__') {
+          return troubleshootResponse;
         }
         // Continue to normal flow below
       }