🔄 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/RegistryStatusCache.ts

@@ -0,0 +1,37 @@
+import { standardCache } from '~/cache';
+import { BaseRegistryCache } from './BaseRegistryCache';
+
+// Status keys
+const INITIALIZED = 'INITIALIZED';
+
+/**
+ * Cache for tracking MCP Servers Registry metadata and status across distributed instances.
+ * Uses Redis-backed storage to coordinate state between leader and follower nodes.
+ * Currently, tracks initialization status to ensure only the leader performs initialization
+ * while followers wait for completion. Designed to be extended with additional registry
+ * metadata as needed (e.g., last update timestamps, version info, health status).
+ * This cache is only meant to be used internally by registry management components.
+ */
+class RegistryStatusCache extends BaseRegistryCache {
+  protected readonly cache = standardCache(`${this.PREFIX}::Status`);
+
+  public async isInitialized(): Promise<boolean> {
+    return (await this.get(INITIALIZED)) === true;
+  }
+
+  public async setInitialized(value: boolean): Promise<void> {
+    await this.set(INITIALIZED, value);
+  }
+
+  private async get<T = unknown>(key: string): Promise<T | undefined> {
+    return this.cache.get(key);
+  }
+
+  private async set(key: string, value: string | number | boolean, ttl?: number): Promise<void> {
+    await this.leaderCheck('set MCP Servers Registry status');
+    const success = await this.cache.set(key, value, ttl);
+    this.successCheck(`set status key "${key}"`, success);
+  }
+}
+
+export const registryStatusCache = new RegistryStatusCache();