feat(booterm): add PTY session registry + listing endpoint

In-memory SessionMeta registry tracks active terminal sessions with
paneId, sessionId, projectPath, title, createdAt, lastActivityAt.
GET /api/term/sessions returns all active sessions as JSON array.
Registry is updated on WS attach and cleaned up on disconnect.

apps/booterm/src/index.ts

@@ -4,6 +4,7 @@ import { loadConfig } from './config.js';
 import { getPool, closeDb } from './db.js';
 import { registerHealthRoutes } from './routes/health.js';
 import { registerTerminalRoutes } from './routes/terminals.js';
+import { registerSessionRoutes } from './routes/sessions.js';
 import { registerWsAttachRoute } from './ws/attach.js';
 
 async function main(): Promise<void> {
@@ -33,6 +34,7 @@ async function main(): Promise<void> {
 
   registerHealthRoutes(app);
   registerTerminalRoutes(app, config.TMUX_CONF_PATH);
+  registerSessionRoutes(app);
   registerWsAttachRoute(app, config.TMUX_CONF_PATH);
 
   const shutdown = async (signal: string) => {

apps/booterm/src/pty/registry.ts

@@ -0,0 +1,44 @@
+export interface SessionMeta {
+  paneId: string;
+  sessionId: string;
+  projectPath: string;
+  title?: string;
+  createdAt: Date;
+  lastActivityAt: Date;
+}
+
+const sessions = new Map<string, SessionMeta>();
+
+export function register(
+  sessionId: string,
+  paneId: string,
+  projectPath: string,
+  title?: string,
+): void {
+  const now = new Date();
+  const existing = sessions.get(paneId);
+  if (existing) {
+    existing.lastActivityAt = now;
+    return;
+  }
+  sessions.set(paneId, {
+    paneId,
+    sessionId,
+    projectPath,
+    title,
+    createdAt: now,
+    lastActivityAt: now,
+  });
+}
+
+export function unregister(paneId: string): void {
+  sessions.delete(paneId);
+}
+
+export function list(): SessionMeta[] {
+  return Array.from(sessions.values());
+}
+
+export function get(paneId: string): SessionMeta | undefined {
+  return sessions.get(paneId);
+}

apps/booterm/src/routes/sessions.ts

@@ -0,0 +1,18 @@
+import type { FastifyInstance } from 'fastify';
+import { list } from '../pty/registry.js';
+
+export function registerSessionRoutes(app: FastifyInstance): void {
+  app.get('/api/term/sessions', async (_req, reply) => {
+    const active = list();
+    return reply.code(200).send({
+      sessions: active.map((s) => ({
+        paneId: s.paneId,
+        sessionId: s.sessionId,
+        projectPath: s.projectPath,
+        title: s.title ?? null,
+        createdAt: s.createdAt.toISOString(),
+        lastActivityAt: s.lastActivityAt.toISOString(),
+      })),
+    });
+  });
+}

apps/booterm/src/ws/attach.ts

@@ -9,6 +9,7 @@ import {
 } from '../pty/manager.js';
 import { attachPty } from '../pty/pty.js';
 import { getUser } from '../auth.js';
+import { register, unregister } from '../pty/registry.js';
 
 export function registerWsAttachRoute(app: FastifyInstance, tmuxConfPath: string): void {
   app.get<{
@@ -57,6 +58,8 @@ export function registerWsAttachRoute(app: FastifyInstance, tmuxConfPath: string
         return;
       }
 
+      register(sid, pid, session.project_path);
+
       let handle: IPty;
       try {
         handle = attachPty({
@@ -157,6 +160,7 @@ export function registerWsAttachRoute(app: FastifyInstance, tmuxConfPath: string
       // teardown happens via the /kill route called from the frontend when the
       // user closes the pane.
       socket.on('close', () => {
+        unregister(pid);
         try {
           handle.kill();
         } catch {