🔄 refactor: MCP Registry System with Distributed Caching (#10191)

* refactor: Restructure MCP registry system with caching

- Split MCPServersRegistry into modular components:
  - MCPServerInspector: handles server inspection and health checks
  - MCPServersInitializer: manages server initialization logic
  - MCPServersRegistry: simplified registry coordination
- Add distributed caching layer:
  - ServerConfigsCacheRedis: Redis-backed configuration cache
  - ServerConfigsCacheInMemory: in-memory fallback cache
  - RegistryStatusCache: distributed leader election state
- Add promise utilities (withTimeout) replacing Promise.race patterns
- Add comprehensive cache integration tests for all cache implementations
- Remove unused MCPManager.getAllToolFunctions method

* fix: Update OAuth flow to include user-specific headers

* chore: Update Jest configuration to ignore additional test files

- Added patterns to ignore files ending with .helper.ts and .helper.d.ts in testPathIgnorePatterns for cleaner test runs.

* fix: oauth headers in callback

* chore: Update Jest testPathIgnorePatterns to exclude helper files

- Modified testPathIgnorePatterns in package.json to ignore files ending with .helper.ts and .helper.d.ts for cleaner test execution.

* ci: update test mocks

---------

Co-authored-by: Danny Avila <danny@librechat.ai>

packages/api/src/mcp/registry/cache/ServerConfigsCacheFactory.ts

@@ -0,0 +1,31 @@
+import { cacheConfig } from '~/cache';
+import { ServerConfigsCacheInMemory } from './ServerConfigsCacheInMemory';
+import { ServerConfigsCacheRedis } from './ServerConfigsCacheRedis';
+
+export type ServerConfigsCache = ServerConfigsCacheInMemory | ServerConfigsCacheRedis;
+
+/**
+ * Factory for creating the appropriate ServerConfigsCache implementation based on deployment mode.
+ * Automatically selects between in-memory and Redis-backed storage depending on USE_REDIS config.
+ * In single-instance mode (USE_REDIS=false), returns lightweight in-memory cache.
+ * In cluster mode (USE_REDIS=true), returns Redis-backed cache with distributed coordination.
+ * Provides a unified interface regardless of the underlying storage mechanism.
+ */
+export class ServerConfigsCacheFactory {
+  /**
+   * Create a ServerConfigsCache instance.
+   * Returns Redis implementation if Redis is configured, otherwise in-memory implementation.
+   *
+   * @param owner - The owner of the cache (e.g., 'user', 'global') - only used for Redis namespacing
+   * @param leaderOnly - Whether operations should only be performed by the leader (only applies to Redis)
+   * @returns ServerConfigsCache instance
+   */
+  static create(owner: string, leaderOnly: boolean): ServerConfigsCache {
+    if (cacheConfig.USE_REDIS) {
+      return new ServerConfigsCacheRedis(owner, leaderOnly);
+    }
+
+    // In-memory mode uses a simple Map - doesn't need owner/namespace
+    return new ServerConfigsCacheInMemory();
+  }
+}