Deduplicate shared helpers and enforce aliased imports (#228)

* Deduplicate string cleanup helpers and not-found responses

* Enforce aliased imports for infra and shared modules

* Enforce @client/@server aliases for deep relative imports

* Deduplicate visa sponsor and location filter definitions

* Use shared city filter export in extractor location checks

shared/src/utils/string.ts

@@ -0,0 +1,7 @@
+export function normalizeWhitespace(value: string): string {
+  return value.replace(/\s+/g, " ").trim();
+}
+
+export function stripHtmlTags(value: string): string {
+  return normalizeWhitespace(value.replace(/<[^>]*>/g, " "));
+}