refactor: move server-agent to agents directory

- Create src/agents/ directory for agent modules
- Move server-agent.ts to new location
- Update import paths in all dependent files:
  - openai-service.ts
  - tools/server-tool.ts
  - routes/handlers/message-handler.ts
  - routes/api/chat.ts

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

src/tools/server-tool.ts

@@ -664,7 +664,7 @@ export async function executeServerAction(
   switch (action) {
     case 'start_consultation': {
       // Import session functions
-      const { saveServerSession } = await import('../server-agent');
+      const { saveServerSession } = await import('../agents/server-agent');
 
       if (!telegramUserId) {
         return '🚫 사용자 인증이 필요합니다.';
@@ -691,7 +691,7 @@ export async function executeServerAction(
     }
 
     case 'continue_consultation': {
-      const { getServerSession, processServerConsultation } = await import('../server-agent');
+      const { getServerSession, processServerConsultation } = await import('../agents/server-agent');
 
       if (!telegramUserId) {
         return '🚫 사용자 인증이 필요합니다.';
@@ -715,7 +715,7 @@ export async function executeServerAction(
     }
 
     case 'cancel_consultation': {
-      const { deleteServerSession } = await import('../server-agent');
+      const { deleteServerSession } = await import('../agents/server-agent');
 
       if (!telegramUserId) {
         return '🚫 사용자 인증이 필요합니다.';
@@ -771,7 +771,7 @@ export async function executeServerAction(
       // 세션에 추천 결과 저장 (선택 기능 활성화)
       if (telegramUserId && env?.DB && recommendationData.recommendations && recommendationData.recommendations.length > 0) {
         try {
-          const { getServerSession, saveServerSession } = await import('../server-agent');
+          const { getServerSession, saveServerSession } = await import('../agents/server-agent');
 
           // 기존 세션 조회 또는 새로 생성
           let session = await getServerSession(env.DB, telegramUserId);