fix: safe status-recommendation flow, MO-016 order independence, brand constant, message codes

- Add a single shared, pure vehicle-status evaluator (app/services/vehicle_status.py)
  used identically by the data-quality scanner, a new non-mutating status-recommendation
  preview endpoint, and a transactional apply endpoint with optimistic-concurrency token
  revalidation -- eliminates the old opaque "calculate and apply" action and the unsafe
  "maintenance + active booking -> auto rented" shortcut. Frontend
  DataQualityIssueDetail.tsx now shows a review/decide/confirm panel with localized
  why/evidence/consequence text in nl-BE/en-GB/fr-BE, with an exact "Change status to
  <status>" confirm action per the brief.
- Fix MO-016 issue-order dependency: resolving the booking-overlap issue before vs.
  after the status-conflict issue now converges on the same final vehicle status,
  proven by test_mo_016_status_conflict_recommendation_is_order_independent.
- Make "Fleet Ops" a non-localizable brand constant (frontend/src/product.ts,
  backend PRODUCT_NAME) via {{productName}} interpolation everywhere the brand name
  appeared in locale prose; add a permanent test guarding against a translation file
  ever defining the brand name or an "appName" key again.
- Convert dynamic backend prose to stable message codes + params: return status
  reasons, audit field/actor-type labels, automation last_error, and search
  section/vehicle/booking/issue results all now carry codes the frontend localizes,
  with raw technical text demoted to a "Technical details" disclosure.
- docs/fleet-ops-correction/: gap audit, i18n inventory, and the vehicle-status
  decision table documenting the evaluator's rules and safe-status principles.

148 backend tests + Ruff + mypy green; Alembic migration verified upgrade/downgrade;
frontend tsc/build and the i18n-coverage Playwright suite green.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/pages/BookingDetail.tsx

@@ -9,6 +9,7 @@ import { StatusBadge } from "../components/Badge";
 import { ReturnForm, ReturnResultPanel } from "../components/ReturnForm";
 import { Icon } from "../components/Icons";
 import { ErrorState, LoadingState, PageHeader } from "../components/PageChrome";
+import { PRODUCT_NAME } from "../product";
 
 export function BookingDetail() {
   const { t } = useTranslation(["bookings", "returns"]);
@@ -73,11 +74,11 @@ export function BookingDetail() {
       </dl></section>
 
       {isReturnAnomalyScenario && !returnResult && canonicalOdometerKm !== null && (
-        <section className="record-surface scenario-callout" aria-label="Demo scenario">
+        <section className="record-surface scenario-callout" aria-label={t("returns:scenario.ariaLabel")}>
           <Icon name="spark" />
           <div>
             <strong>{t("returns:scenario.title")}</strong>
-            <p>{t("returns:scenario.body", { odometer: formatNumber(canonicalOdometerKm) })}</p>
+            <p>{t("returns:scenario.body", { odometer: formatNumber(canonicalOdometerKm), productName: PRODUCT_NAME })}</p>
           </div>
         </section>
       )}