refactor: remove dead code and unused exports

Delete proxy-auth.ts, types/index.ts, staff-user.ts+test, local-imports.ts+test (only used by their own tests). Remove unused foundation exports: sanitizeFilename, canonicalizeFormValue, canonicalizeFormData, ConflictError, getRequestStore, getClientIp, elapsed. Remove stale TODO comments from rank-authority.ts and notice.ts. Fix biome lint warnings in catalog-repair.ts.

src/lib/admin/rank-authority.ts

@@ -1,4 +1,3 @@
-// TODO: Check of dit bestand weg kan — uitsluitend gebruikt door eigen test
 import type { AuthorizationActor } from "@/lib/admin/authorization-policy";
 
 export interface RankAuthorityDb {