Add plugin framework and settings UI

server/src/services/plugin-stream-bus.ts

@@ -0,0 +1,81 @@
+/**
+ * In-memory pub/sub bus for plugin SSE streams.
+ *
+ * Workers emit stream events via JSON-RPC notifications. The bus fans out
+ * each event to all connected SSE clients that match the (pluginId, channel,
+ * companyId) tuple.
+ *
+ * @see PLUGIN_SPEC.md §19.8 — Real-Time Streaming
+ */
+
+/** Valid SSE event types for plugin streams. */
+export type StreamEventType = "message" | "open" | "close" | "error";
+
+export type StreamSubscriber = (event: unknown, eventType: StreamEventType) => void;
+
+/**
+ * Composite key for stream subscriptions: pluginId:channel:companyId
+ */
+function streamKey(pluginId: string, channel: string, companyId: string): string {
+  return `${pluginId}:${channel}:${companyId}`;
+}
+
+export interface PluginStreamBus {
+  /**
+   * Subscribe to stream events for a specific (pluginId, channel, companyId).
+   * Returns an unsubscribe function.
+   */
+  subscribe(
+    pluginId: string,
+    channel: string,
+    companyId: string,
+    listener: StreamSubscriber,
+  ): () => void;
+
+  /**
+   * Publish an event to all subscribers of (pluginId, channel, companyId).
+   * Called by the worker manager when it receives a stream notification.
+   */
+  publish(
+    pluginId: string,
+    channel: string,
+    companyId: string,
+    event: unknown,
+    eventType?: StreamEventType,
+  ): void;
+}
+
+/**
+ * Create a new PluginStreamBus instance.
+ */
+export function createPluginStreamBus(): PluginStreamBus {
+  const subscribers = new Map<string, Set<StreamSubscriber>>();
+
+  return {
+    subscribe(pluginId, channel, companyId, listener) {
+      const key = streamKey(pluginId, channel, companyId);
+      let set = subscribers.get(key);
+      if (!set) {
+        set = new Set();
+        subscribers.set(key, set);
+      }
+      set.add(listener);
+
+      return () => {
+        set!.delete(listener);
+        if (set!.size === 0) {
+          subscribers.delete(key);
+        }
+      };
+    },
+
+    publish(pluginId, channel, companyId, event, eventType: StreamEventType = "message") {
+      const key = streamKey(pluginId, channel, companyId);
+      const set = subscribers.get(key);
+      if (!set) return;
+      for (const listener of set) {
+        listener(event, eventType);
+      }
+    },
+  };
+}