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/services/catalog-repair.ts

@@ -261,7 +261,7 @@ function derivePageCaption(classname: string, fallback: string): string {
 		const re = new RegExp(`^${prefix.replace(/_/g, "[_]?")}(?:_)?(\\d*)`, "i");
 		const m = lower.match(re);
 		if (m) {
-			const matchEnd = m.index! + m[0].length;
+			const matchEnd = (m.index ?? 0) + m[0].length;
 			const nextChar = lower[matchEnd];
 			if (
 				!nextChar ||
@@ -278,7 +278,7 @@ function derivePageCaption(classname: string, fallback: string): string {
 	// Also try matching suffix patterns (e.g., "something_xmas2025").
 	for (const prefix of sortedPrefixes) {
 		const re = new RegExp(
-			`${prefix.replace(/_/g, "[_]?")}(?:_)?(\\d{4})` + "(_|$)",
+			`${prefix.replace(/_/g, "[_]?")}(?:_)?(\\d{4})(_|$)`,
 			"i",
 		);
 		const m = lower.match(re);