Extend browser admin lifecycle actions

Support browser reboot and HTTPS stop through deferred control, plus
exact
`web certificate rotate --force` handoff to the dispatcher. Add typed
request
validation and focused boundary and lifecycle coverage.

docs/agent/architecture.md

@@ -171,6 +171,10 @@ For SSH, standard output/error is redirected to the invoking session's bounded o
 
 Admin SSH `exit`, remote reboot, SSH stop/disconnect, and host-key rotate/reset use deferred control. The control task waits up to ten seconds for command state plus administration and transport application buffers to clear, then adds a short delay; this is a bounded best-effort heuristic, not peer-delivery confirmation. UART0 invokes these actions synchronously. User mutations and their revocations are not part of this mechanism. UART0 linenoise and the SSH editor consume the same manually maintained completion matcher and candidate formatter, so the two administration routes cannot drift in offered or displayed ambiguous completions; the hints can still drift from command registration and are not an authorization list.
 
+The first 8D.7 slice enables browser-admin reboot and HTTPS stop through the same control task. `web stop` is deferred only for browser origin; UART0/admin SSH keep their synchronous HTTPS-stop path. WEB performs authoritative cookie/principal/token validation after drain and delay, then calls lifecycle APIs outside console locks, never socket IO. Console snapshots expose pending deferral; HTTPD discards buffered/new input observed during it and latches each frame's discard decision across payload reception/cancellation. HTTPS stop intentionally closes both browser routes.
+
+The second 8D.7 slice additionally permits exact parsed browser `web certificate rotate --force`. The request queue has a typed command-line/deferred-action union with unchanged capacity. An immutable owner `dispatcher_actions` mask sends certificate work, after the bounded drain and 200 ms delay, nonblockingly to the existing 12 KiB dispatcher rather than the 4 KiB control stack; zero mask retains SSH control-task behavior. Pending input remains gated through queueing/execution. Dispatcher token/principal/session/owner revalidation and an executing-slot reservation prevent stale execution or reuse during self-detach; WEB validates currentness again before lifecycle APIs. Transactional certificate generation/persistence commits before stop → start; generation/commit error skips lifecycle calls, stop error skips start and retains HTTPD ownership, and later lifecycle failure does not roll back committed material. HTTPD alone owns socket IO. Successful restart invalidates browser sessions and both routes; certificate trust and login must be renewed, while USB/UART0/SSH remain available. Account/legacy-credential/network/restricted SSH mutations remain blocked. No new tasks, depths, routes, assets or stack sizes. Drain/acknowledgement bounds are not execution deadlines or delivery guarantees; owner-mask/local-scratch target layout and control/dispatcher stack margins remain unmeasured (host sizeof is not target proof).
+
 ## Wi-Fi and persistence
 
 `wifi_config` owns a fixed-width versioned NVS schema with four prioritized station profiles and AP policy `off`, `fallback`, or `always`. Missing configuration generates per-device defaults including a random AP password. Invalid stored data is generally left untouched while RAM defaults are used.