refactor: Enhance GenerationJobManager with In-Memory Implementations

- Introduced InMemoryJobStore, InMemoryEventTransport, and InMemoryContentState for improved job management and event handling.
- Updated GenerationJobManager to utilize these new implementations, allowing for better separation of concerns and easier maintenance.
- Enhanced job metadata handling to support user messages and response IDs for resumable functionality.
- Improved cleanup and state management processes to prevent memory leaks and ensure efficient resource usage.

packages/api/src/stream/interfaces/IJobStore.ts

@@ -0,0 +1,139 @@
+import type { Agents } from 'librechat-data-provider';
+import type { StandardGraph } from '@librechat/agents';
+
+/**
+ * Job status enum
+ */
+export type JobStatus = 'running' | 'complete' | 'error' | 'aborted';
+
+/**
+ * Serializable job data - no object references, suitable for Redis/external storage
+ */
+export interface SerializableJobData {
+  streamId: string;
+  userId: string;
+  status: JobStatus;
+  createdAt: number;
+  completedAt?: number;
+  conversationId?: string;
+  error?: string;
+
+  /** User message metadata */
+  userMessage?: {
+    messageId: string;
+    parentMessageId?: string;
+    conversationId?: string;
+    text?: string;
+  };
+
+  /** Response message ID for reconnection */
+  responseMessageId?: string;
+
+  /** Sender name for UI display */
+  sender?: string;
+
+  /** Whether sync has been sent to a client */
+  syncSent: boolean;
+
+  /** Serialized final event for replay */
+  finalEvent?: string;
+}
+
+/**
+ * Resume state for reconnecting clients
+ */
+export interface ResumeState {
+  runSteps: Agents.RunStep[];
+  aggregatedContent: Agents.MessageContentComplex[];
+  userMessage?: SerializableJobData['userMessage'];
+  responseMessageId?: string;
+  conversationId?: string;
+  sender?: string;
+}
+
+/**
+ * Interface for job storage backend.
+ * Implementations can use in-memory Map, Redis, KV store, etc.
+ */
+export interface IJobStore {
+  /** Create a new job */
+  createJob(
+    streamId: string,
+    userId: string,
+    conversationId?: string,
+  ): Promise<SerializableJobData>;
+
+  /** Get a job by streamId */
+  getJob(streamId: string): Promise<SerializableJobData | null>;
+
+  /** Find active job by conversationId */
+  getJobByConversation(conversationId: string): Promise<SerializableJobData | null>;
+
+  /** Update job data */
+  updateJob(streamId: string, updates: Partial<SerializableJobData>): Promise<void>;
+
+  /** Delete a job */
+  deleteJob(streamId: string): Promise<void>;
+
+  /** Check if job exists */
+  hasJob(streamId: string): Promise<boolean>;
+
+  /** Get all running jobs (for cleanup) */
+  getRunningJobs(): Promise<SerializableJobData[]>;
+
+  /** Cleanup expired jobs */
+  cleanup(): Promise<number>;
+}
+
+/**
+ * Interface for pub/sub event transport.
+ * Implementations can use EventEmitter, Redis Pub/Sub, etc.
+ */
+export interface IEventTransport {
+  /** Subscribe to events for a stream */
+  subscribe(
+    streamId: string,
+    handlers: {
+      onChunk: (event: unknown) => void;
+      onDone?: (event: unknown) => void;
+      onError?: (error: string) => void;
+    },
+  ): { unsubscribe: () => void };
+
+  /** Publish a chunk event */
+  emitChunk(streamId: string, event: unknown): void;
+
+  /** Publish a done event */
+  emitDone(streamId: string, event: unknown): void;
+
+  /** Publish an error event */
+  emitError(streamId: string, error: string): void;
+
+  /** Get subscriber count for a stream */
+  getSubscriberCount(streamId: string): number;
+
+  /** Listen for all subscribers leaving */
+  onAllSubscribersLeft(streamId: string, callback: () => void): void;
+}
+
+/**
+ * Interface for content state management.
+ * Separates volatile content state from persistent job data.
+ * In-memory only - not persisted to external storage.
+ */
+export interface IContentStateManager {
+  /** Set content parts reference (in-memory only) */
+  setContentParts(streamId: string, contentParts: Agents.MessageContentComplex[]): void;
+
+  /** Get content parts */
+  getContentParts(streamId: string): Agents.MessageContentComplex[] | null;
+
+  /** Set graph reference for run steps */
+  setGraph(streamId: string, graph: StandardGraph): void;
+
+  /** Get run steps from graph */
+  getRunSteps(streamId: string): Agents.RunStep[];
+
+  /** Clear content state for a job */
+  clearContentState(streamId: string): void;
+}