Add a CEO-bound, header-token-only gate (require_panel_token) at the route
level of the prompter_live + secretary_live bridges, which were the only
panel-facing API surface that ran unauthenticated. It mirrors the WS
_require_panel_token and _check_agent_auth_token contracts: in dev
(ROBOCO_AGENT_AUTH_REQUIRED unset) a missing token is allowed; a
presented-but-forged token is rejected even in dev; in prod nginx already
injects the CEO-signed X-Agent-Token on /api/ for GET + POST, so the SSE
stream (EventSource can't set headers) and the POSTs are now checked instead
of anonymous. Applied to start/stream/status/messages/stop on both routers;
preview_live_batch switched from CurrentAgentContext+noqa to the route-level
gate (genuinely auth-only). confirm/confirm-batch/re-interview keep
CurrentAgentContext (they use agent.identity). The container->relay /events
callback is intentionally left ungated (internal Docker network, opaque
session id) — gated by a test sentinel so Option B (spawn+SDK token wiring)
is a deliberate future decision. No panel/nginx/spawn/SDK changes; master
merge invariant untouched. 22 new TDD auth tests, 492 api tests green.
