polish: rebrand to Fleet Ops, add trilingual i18n, adaptive demo guide, and UX overhaul

Rebrands the product from MobilityOps to Fleet Ops across the UI, backend defaults and
knowledge base, and makes nl-BE/en-GB/fr-BE full first-class languages: i18next with
eager-bundled per-namespace resources, a persisted accessible language switcher (topbar
and mobile drawer), locale-aware date/number formatting, and a coverage test that fails
the build on any missing or empty translation key.

Backend dynamic content (demo scenarios, blocked-reason text, integration status) moves
from fixed English/Dutch prose to stable message codes + params so the frontend can
localize it; the demo knowledge base gains a fully translated NL/EN/FR procedure corpus
(11 documents each) with per-language retrieval and localized evidence-state messages.

The Demo Guide becomes breakpoint-adaptive: a docked rail on extra-wide desktop, a
floating panel that auto-collapses to a persistent, closable progress chip on standard
desktop/tablet, and a collapsed/half/full bottom sheet on mobile -- with scroll+focus+
highlight on "go to this step", Escape handling, and reduced-motion support.

The Data Quality Workbench gets accessible choice-card decisions with a clear primary/
secondary/tertiary action hierarchy; the Automation ledger groups repeated successes and
uses meaningful short refs; the Audit trail groups events by correlation id with human
action labels and readable before/after diffs. Attention Queue, Today's movements,
Vehicles, Bookings and Data Quality rows are fully clickable (stretched-link pattern)
with independent secondary links, keyboard support and mobile touch targets.

Fixes a topbar overflow on mobile caused by the new language switcher (moved into the
mobile drawer at <=960px) and two dangling aria-labelledby references introduced this
session. Updates all affected Playwright specs for the new nl-BE default and the new
Audit/DemoGuide DOM structure, and adds new i18n-coverage, demo-guide-adaptive and
clickable-rows specs. 131 backend tests, Ruff and mypy, and 71 Playwright tests pass.

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

frontend/src/i18n/locales/fr-BE/knowledge.json

@@ -0,0 +1,41 @@
+{
+  "eyebrow": "Assurance / Connaissances étayées",
+  "title": "Connaissance des procédures",
+  "description": "Posez des questions opérationnelles. Les réponses ne s'affichent que lorsque {{provider}} renvoie suffisamment de preuves citées.",
+  "providerDemo": "la base de connaissances de démo",
+  "providerRagcore": "RAGcore",
+  "statusAvailable": "Disponible",
+  "statusUnavailable": "Indisponible",
+  "proceduresIndexed": "{{count}} procédures indexées",
+  "providerNote": "Cette démo répond à partir d'un petit ensemble fixe de procédures indexées — pas d'une connexion RAGcore en direct. Un backend RAGcore en direct reprendra plus tard la même interface sans changer le fonctionnement de cette page.",
+  "askHeading": "Poser une question de procédure",
+  "askSubheading": "Recherche → vérification des preuves → réponse étayée",
+  "questionLabel": "Question",
+  "questionPlaceholder": "p. ex. Que dois-je faire quand un véhicule revient endommagé ?",
+  "ask": "Demander",
+  "asking": "Question en cours…",
+  "askFailed": "Impossible de joindre le service de connaissances.",
+  "suggestedLabel": "Essayez :",
+  "suggestedQuestions": [
+    "Que dois-je faire quand un véhicule revient avec des dommages ?",
+    "Comment enregistrer le retour d'un véhicule ?",
+    "Quand un véhicule peut-il redevenir disponible ?",
+    "Qui examine un relevé de kilométrage inhabituel ?",
+    "Quels contrôles sont requis avant le départ ?"
+  ],
+  "emptyTitle": "Des preuves avant les réponses",
+  "emptyDescription": "Posez des questions sur les retours, les dommages, les inspections ou une autre procédure indexée. Fleet Ops n'invente jamais de réponse en l'absence de preuves.",
+  "retrievalFlow": {
+    "question": "Question",
+    "sources": "Sources",
+    "answer": "Réponse"
+  },
+  "questionLabelExchange": "Question",
+  "evidenceStates": {
+    "grounded": "Étayé par des procédures citées",
+    "insufficient": "Preuves insuffisantes",
+    "unavailable": "Service de connaissances indisponible"
+  },
+  "unavailableBody": "Le service de connaissances est actuellement inaccessible. Les fonctions opérationnelles ne sont pas affectées — réessayez plus tard.",
+  "sourceVersion": "v{{version}}"
+}