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/types/index.ts

@@ -1 +0,0 @@
-export type { DataTableColumn, ListParams, PaginatedResult } from "./common";