Function switchSession

src/bootstrap/state.ts:474–485

(
  sessionId: SessionId,
  projectDir: string | null = null,
)

 *   carries over from the previous session.
 */
export function switchSession(
  sessionId: SessionId,
  projectDir: string | null = null,
): void {
  // Drop the outgoing session's plan-slug entry so the Map stays bounded
  // across repeated /resume. Only the current session's slug is ever read
  // (plans.ts getPlanSlug defaults to getSessionId()).
  STATE.planSlugCache.delete(STATE.sessionId)
  STATE.sessionId = sessionId
  STATE.sessionProjectDir = projectDir
  sessionSwitched.emit(sessionId)
}

const sessionSwitched = createSignal<[id: SessionId]>()