feat(realtime): export RealtimeHandler type from SDK

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ImriKochWix

src/index.ts

@@ -110,6 +110,8 @@ export type {
 
 export type { SsoModule, SsoAccessTokenResponse } from "./modules/sso.types.js";
 
+export { RealtimeHandler, type Conn } from "./realtime-handler.js";
+
 export type {
   ConnectorsModule,
   UserConnectorsModule,

src/realtime-handler.ts

@@ -0,0 +1,41 @@
+/**
+ * Type-only base class for Realtime Handlers.
+ *
+ * Import and extend this in your handler files:
+ *   import { RealtimeHandler } from "@base44/sdk";
+ *   export class MyHandler extends RealtimeHandler { ... }
+ *
+ * At deploy time the bundler replaces this import with the compiled
+ * Cloudflare Durable Object implementation — this file provides types only.
+ */
+
+export interface Conn {
+  userId: string;
+  appId: string;
+  instanceId: string;
+  send(data: unknown): void;
+  reject(code: number, reason: string): void;
+}
+
+export abstract class RealtimeHandler<_State = unknown, Message = unknown> {
+  abstract handleConnect(conn: Conn): void | Promise<void>;
+  abstract handleMessage(conn: Conn, msg: Message): void | Promise<void>;
+  abstract handleClose(conn: Conn): void | Promise<void>;
+  abstract handleTick(): void | Promise<void>;
+
+  protected broadcast(_data: unknown): void {
+    throw new Error("RealtimeHandler.broadcast() is only available inside a deployed handler");
+  }
+
+  protected getConnections(): Conn[] {
+    throw new Error("RealtimeHandler.getConnections() is only available inside a deployed handler");
+  }
+
+  protected startLoop(_ms: number): Promise<void> {
+    throw new Error("RealtimeHandler.startLoop() is only available inside a deployed handler");
+  }
+
+  protected stopLoop(): Promise<void> {
+    throw new Error("RealtimeHandler.stopLoop() is only available inside a deployed handler");
+  }
+}