Implement HTTPS lifecycle and reboot controls

docs/agent/architecture.md

@@ -110,6 +110,10 @@ TinyUSB callbacks enqueue/copy data and state; the transport task owns broker li
 
 ### HTTPS, WebSocket, and web serial
 
+**8D.20 integrated lifecycle (supersedes prerequisite-only status below):** `web_lifecycle_settings` admits strict current-admin cookie/Origin/CSRF stop/restart/reboot through three optional routes. One original-login operation slot and nonreused ID,256-byte/four-receive request,128-byte snapshot/96-byte result. Only after synchronous response send succeeds does HTTPD queue an ID callback; it hands that ID without waiting to the existing four-entry dispatcher. No request/fd/socket/operation pointer escapes the handler. Two-second ACK and30-second post-validation dequeue deadlines precede owner admission, not lifecycle completion. Lost HTTPD work retains one reservation until callback or successful destruction, avoiding late-work accumulation; failed destruction preserves it. Dispatcher reserves execution, revalidates original session/current admin and calls canonical generation-conditional owner APIs outside locks. Restart invalidates logins but retains its owner reservation through start; later revocation is not cancellation. Conditional reboot reserves the HTTPS generation then invokes the shared canonical `esp_restart()` primitive outside locks, with no console self-cleanup or HTTPD stop wait. UI explicit confirmation/manual results/15-second whole request fences and no replay/restore; existing Network reused.39 handlers/six sockets and unchanged tasks/stacks/timers/queue depth. Full API, uncertainty, SDK/reset audit and resource limits: `docs/phase8d20_implementation.md`.
+
+**Historical 8D.20 internal owner prerequisite (superseded above):** `web_server` exposes a zero-wait scalar management snapshot and off-HTTPD generation-conditional stop/restart APIs. A firmware-lifetime saturated generation advances under the existing lifecycle mutex on every admitted canonical start/stop, including failed attempts; counter clear and repeated init do not restore old tokens. Conditional admission rejects failed cleanup, transition, absent server or exhausted generation. Reserved restart keeps `s_transitioning` true across successful stop into private start, with no unreserved stopped gap; external lifecycle calls remain outside the mutex. Stop failure skips start, partial-start cleanup failure retains ownership, and canonical stop/start remain recovery after saturation/failure. Repeated init preserves retained lifecycle errors. These APIs have no production caller yet and perform no authorization or ACK handoff; HTTP routes/UI/typed reboot are unimplemented. A future dispatcher must validate the original login and bound ACK handling before admission, never call shutdown from HTTPD or describe admitted work as cancelled by later revocation. Contract and incomplete scope: `docs/phase8d20_implementation.md`.
+
 `web_server` runs HTTPS only on port 443 using the device-specific self-signed P-256 certificate from `web_security`. Current routes provide the UI, static assets, status, ticket issuance, and serial WebSocket upgrade.
 
 HTTPS login uses `user_database` and opaque server-side cookie sessions; Basic authentication and its cache are removed in 8D.3. No legacy credential is imported, synchronized or consulted for authentication. Both roles retain the same shipped web status/serial UI. 8D.5 adds an admin-only backend without a normal UI entry.