Add typed serial settings operations

Route bounded admin mutations through the existing administration
dispatcher,
covering apply, lifecycle, persistence, authorization, and result
tracking.
Add the browser controls, automatic result refresh, regression coverage,
and
phase documentation.

docs/agent/code-map.md

@@ -76,6 +76,8 @@ This is a semantic map, not a complete file inventory. Start here, then read the
 - 8D.6 UI: `web_ui.c` adds admin-only Serial/Admin selection and explicit admin open/close through existing endpoints. Serial socket/client/lease survives mode switches; hidden output drains into independent 5,000-line/64 KiB-pending terminals with visible browser-drop counts. Selected keyboard only; logout/expiry/pagehide closes both with handler cleanup. Session identity changes require a clean document before adopting the view; same-session restore retains hidden-until-validated buffers. Fit readiness retries are bounded to three and cache only success. Focused `tests/web_ui_session/run.py` has 17 groups plus toolbar-order/CSP checks. 8D.6 is user-validated; telemetry, evidence limits and 8D.7 handoff are in `docs/phase8d6_implementation.md`. Numeric reserves remain open; no 8D.7 restriction change.
 - 8D.8: `web_ui.c` adds admin-only Settings/Serial without socket/lease changes. `web_server.c` exposes optional admin-only bodyless `GET /api/settings/serial`, eight working serial values, 256-byte response, no writes/NVS. `serial_service_get_snapshot()` is a zero-wait consistent config/running copy. `web_httpd_register_optional_get()` stages both new-route allocations before table publication (installed IDF public registration leaves a dangling descriptor on name-allocation failure); only Settings uses this startup/exact-GET adapter. 17 URI slots, six sockets/no LRU, no new task. Tests: cookie auth `--settings` (5 groups), UI (21 groups), lifecycle (12 groups). Implemented/build-verified, target/signoff pending; exact accounting and inherited registration-audit followup: `docs/phase8d8_implementation.md`. M2 remains signed off; no 8D.9.
 
+- 8D.9: `web_serial_settings.{c,h}` owns strict 256-byte typed mutation admission and one session-bound pending/result slot. Existing `admin_ssh_console` dispatcher consumes only an ID, revalidates currentness/dequeue deadline and calls canonical serial APIs. `web_server.c` adds optional GET/POST `/api/settings/serial-operation` (19 handlers total); `web_cookie_auth_require_json()` retains Origin/CSRF/admin policy, private optional registration supports exact GET/POST. UI adds explicit framing/lifecycle/persistence with automatic completion checks (1 s, at most 10 GETs/15 s overall), refresh on known terminal results and manual uncertainty recovery without socket/lease changes. Settings stay visible/stale while pending; only Reset confirms NVS overwrite; selecting the current view is a no-op. `/api/status` uses a consistent zero-wait serial snapshot (`running:null` when unavailable). Tests: cookie `--serial-settings` (10 groups), `--settings` (6), UI (35 after UX refinement), console boundary and lifecycle (13). Build verified, target/signoff pending; bounds and failure contracts: `docs/phase8d9_implementation.md`. Supersedes 8D.8's no-8D.9 status above.
+
 ### Browser admin backend (8D.5)
 
 - **8D.7 current status (2026-09-07): implemented scope validated; M2 explicitly signed off by the user ("Jupp, sign M2 off").** Supersedes M2-open/target-pending/continuation statements in the historical slices below; accepted M2 does not require revalidation. User verified certificate rotation and web start/stop via UART0/SSH admin/web admin, restarting after browser stop via another route; full mix without broker drops up to 230400 baud after external adapter correction is user-reported. Intermittent supported two serial + one admin admission failures, recently not recurring, are accepted nonblocking, not fixed. Browser self/generated/key/legacy-credential and other owner command restrictions remain deferred; bootstrap/recovery remain permanently UART0-only. Numeric memory reserves/stack margins remain unapproved; no full parity or individual unreported checklist passes. Next: separately requested 8D.8 read-only settings entry and Serial page; sign-off alone authorizes no implementation. Evidence: `docs/phase8d7_implementation.md`.