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/i18n/locales/en-GB/demo.json

@@ -83,7 +83,7 @@
         "whatYouWillSee": "An overview of what's functionally implemented in this demo, what's synthetic, and which integrations aren't live yet.",
         "whyItMatters": "A demo is only convincing if visitors can verify for themselves what really works and what's still ahead.",
         "startAction": "Read the 'About this demo' page.",
-        "expectedOutcome": "You can explain yourself what Fleet Ops is and isn't, with no verbal explanation needed."
+        "expectedOutcome": "You can explain yourself what {{productName}} is and isn't, with no verbal explanation needed."
       }
     }
   },
@@ -146,16 +146,16 @@
   },
   "about": {
     "eyebrow": "About this demo",
-    "title": "What Fleet Ops is and isn't",
+    "title": "What {{productName}} is and isn't",
     "description": "{{orgName}} is a fictional rental organisation that makes this demo tangible — not a real company.",
     "loading": "Loading demo information…",
     "ctaTitle": "Prefer to jump right in?",
     "ctaBody": "The guided demo walks through all eight steps above in practice.",
     "ctaButton": "Start guided demo",
     "problemTitle": "The fictional problem",
-    "problemBody": "{{orgName}} rents around 50 campers and vans from one main location. Bookings, returns, customer records and maintenance used to live in separate spreadsheets and verbal hand-offs, so problems (duplicate customers, incorrect odometer readings, double-booked vehicles) only surfaced late. Fleet Ops shows how one connected system flags these problems early and lets them be resolved under control.",
+    "problemBody": "{{orgName}} rents around 50 campers and vans from one main location. Bookings, returns, customer records and maintenance used to live in separate spreadsheets and verbal hand-offs, so problems (duplicate customers, incorrect odometer readings, double-booked vehicles) only surfaced late. {{productName}} shows how one connected system flags these problems early and lets them be resolved under control.",
     "scopeTitle": "Who it's for and its scope",
-    "scopeBody": "This demo is for anyone who wants to see how Fleet Ops tackles operational problems at a small rental company: Operations Managers and Rental Employees, and anyone evaluating the approach. The scope is deliberately focused on one connected proof of concept — no accounting, no payments, no public reservations, no full CRM or ERP.",
+    "scopeBody": "This demo is for anyone who wants to see how {{productName}} tackles operational problems at a small rental company: Operations Managers and Rental Employees, and anyone evaluating the approach. The scope is deliberately focused on one connected proof of concept — no accounting, no payments, no public reservations, no full CRM or ERP.",
     "realTitle": "What really works",
     "realBody": "Everything below is functional code, not just a mockup: role-based access and sessions, vehicle and booking management, return processing with server-side validation, five data-quality rules each with its own resolution step, a full audit trail, automated delivery to n8n with bounded retries, Docker-based deployment, and an automated test suite (backend and Playwright end-to-end).",
     "syntheticTitle": "What's synthetic",