feat(overview): resolve dashboard layout from permissions, not role keys

role-dashboards.config.ts's ROLE_LAYOUTS was a hand-typed table of ~40
raw role/position keys (including edr_freight_app/xxx ad-hoc
sub-positions), matched against the user's held keys client-side.
Replaced with resolveOverviewLayout(), which just picks the
highest-priority key out of whatever GET /overview/layouts returns —
the same 'server filters by permission, frontend renders what comes
back' shape Reports already uses, so the frontend no longer needs to
know any individual permission key.

Hard cutover: no fallback to the old key table. Positions not covered
by the previous commit's grants (the ad-hoc department sub-positions)
will render the executive layout until granted a layout permission.

apps/edr-freight-web/backoffice/src/constants/QUERY_KEYS.ts

@@ -235,6 +235,7 @@ export const QUERY_KEYS = {
 
   OVERVIEW: {
     ROOT: ["overview"] as const,
+    layouts: () => ["overview", "layouts"] as const,
     dashboard: (range?: string) =>
       ["overview", "dashboard", range ?? "30d"] as const,
     bookingsTab: (range?: string) =>

apps/edr-freight-web/backoffice/src/constants/URLS.ts

@@ -184,6 +184,7 @@ export const URL_CONSTANTS = {
 
   OVERVIEW: {
     BASE: "/overview",
+    LAYOUTS: "/overview/layouts",
     BOOKINGS: "/overview/bookings",
     CONTRACTS: "/overview/contracts",
     BILLING: "/overview/billing",