fix: fall back to tool pods when redis is unavailable

dap-gateway/src/main/java/io/shinhanlife/dap/mcg/presentation/McpRouterController.java

@@ -113,11 +113,16 @@ public class McpRouterController {
     }
 
     private List<ToolMetadata> fetchAllActiveTools() {
-        List<ToolMetadata> activeTools = redisRegistryService.getAllTools()
-                .stream()
-                .filter(ToolMetadata::getVisible)
-                .collect(Collectors.toList());
-                
+        List<ToolMetadata> activeTools = new ArrayList<>();
+        try {
+            activeTools.addAll(redisRegistryService.getAllTools()
+                    .stream()
+                    .filter(ToolMetadata::getVisible)
+                    .collect(Collectors.toList()));
+        } catch (org.springframework.data.redis.RedisConnectionFailureException exception) {
+            log.warn("Redis is unavailable. Fetching tools from configured fallback Tool Pods instead.");
+        }
+
         Set<String> knownTools = activeTools.stream()
                 .map(ToolMetadata::getUid)
                 .collect(Collectors.toSet());