fix(admin): bulk-tabling/catchtable SSE timeout 10분 → 3시간

- 대량 백필(700+건 ≈ 100분) 시 10분 SSE timeout으로 중간 끊김
- emit() 실패 시 마지막 cache.flush + complete 누락 → 3시간으로 확장

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend-java/src/main/java/com/tasteby/controller/RestaurantController.java

@@ -175,7 +175,7 @@ public class RestaurantController {
     @PostMapping("/bulk-tabling")
     public SseEmitter bulkTabling() {
         AuthUtil.requireAdmin();
-        SseEmitter emitter = new SseEmitter(600_000L);
+        SseEmitter emitter = new SseEmitter(10_800_000L); // 3h — 대량 백필 대응
 
         executor.execute(() -> {
             try {
@@ -309,7 +309,7 @@ public class RestaurantController {
     @PostMapping("/bulk-catchtable")
     public SseEmitter bulkCatchtable() {
         AuthUtil.requireAdmin();
-        SseEmitter emitter = new SseEmitter(600_000L);
+        SseEmitter emitter = new SseEmitter(10_800_000L); // 3h — 대량 백필 대응
 
         executor.execute(() -> {
             try {