batch3 T3: broker user channel + /api/ws/user + project/session/inference emits

- broker.subscribeUser/publishUser via separate user topics map
- /api/ws/user WS route subscribes to the user channel
- projects/sessions POST/DELETE handlers emit lifecycle frames
- inference 3 terminal-state sites emit session_updated with RETURNING

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/routes/sessions.ts

@@ -2,6 +2,7 @@ import type { FastifyInstance } from 'fastify';
 import { z } from 'zod';
 import type { Sql } from '../db.js';
 import type { Config } from '../config.js';
+import type { Broker } from '../services/broker.js';
 import type { Session } from '../types/api.js';
 import { getSetting } from './settings.js';
 
@@ -26,7 +27,8 @@ async function resolveDefaultModel(sql: Sql, config: Config): Promise<string> {
 export function registerSessionRoutes(
   app: FastifyInstance,
   sql: Sql,
-  config: Config
+  config: Config,
+  broker: Broker
 ): void {
   app.get<{ Params: { id: string } }>(
     '/api/projects/:id/sessions',
@@ -86,6 +88,11 @@ export function registerSessionRoutes(
         `;
         return session!;
       });
+      broker.publishUser(req.user!, {
+        type: 'session_created',
+        session: row,
+        project_id: row.project_id,
+      });
       reply.code(201);
       return row;
     }
@@ -133,11 +140,16 @@ export function registerSessionRoutes(
   app.delete<{ Params: { id: string } }>(
     '/api/sessions/:id',
     async (req, reply) => {
-      const result = await sql`DELETE FROM sessions WHERE id = ${req.params.id}`;
-      if (result.count === 0) {
+      const id = req.params.id;
+      const deleted = await sql<{ project_id: string }[]>`
+        DELETE FROM sessions WHERE id = ${id} RETURNING project_id
+      `;
+      if (deleted.length === 0) {
         reply.code(404);
         return { error: 'not found' };
       }
+      const project_id = deleted[0]!.project_id;
+      broker.publishUser(req.user!, { type: 'session_deleted', session_id: id, project_id });
       reply.code(204);
       return null;
     }