feat(booterm): PTY session metadata, terminal registry, WS attach enhancements

- Add PTY session metadata tracking (title, description, parent agent)
- Extend terminal registry: structured session metadata
- Extend WS attach: session-aware WebSocket lifecycle
- Extend routes: terminals and sessions with metadata

apps/booterm/src/config.ts

@@ -7,6 +7,8 @@ const ConfigSchema = z.object({
   DATABASE_URL: z.string().url(),
   LOG_LEVEL: z.string().default('info'),
   TMUX_CONF_PATH: z.string().default('/etc/booterm/tmux.conf'),
+  PTY_IDLE_TIMEOUT_SECONDS: z.coerce.number().int().min(0).default(0),
+  PTY_ABSOLUTE_TIMEOUT_SECONDS: z.coerce.number().int().min(0).default(0),
 });
 
 type Config = z.infer<typeof ConfigSchema>;