🔄 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/BaseRegistryCache.ts

@@ -0,0 +1,26 @@
+import type Keyv from 'keyv';
+import { isLeader } from '~/cluster';
+
+/**
+ * Base class for MCP registry caches that require distributed leader coordination.
+ * Provides helper methods for leader-only operations and success validation.
+ * All concrete implementations must provide their own Keyv cache instance.
+ */
+export abstract class BaseRegistryCache {
+  protected readonly PREFIX = 'MCP::ServersRegistry';
+  protected abstract readonly cache: Keyv;
+
+  protected async leaderCheck(action: string): Promise<void> {
+    if (!(await isLeader())) throw new Error(`Only leader can ${action}.`);
+  }
+
+  protected successCheck(action: string, success: boolean): true {
+    if (!success) throw new Error(`Failed to ${action} in cache.`);
+    return true;
+  }
+
+  public async reset(): Promise<void> {
+    await this.leaderCheck(`reset ${this.cache.namespace} cache`);
+    await this.cache.clear();
+  }
+}