Fix: Enable TypeScript strict mode

src/lib/errorHandler.ts

@@ -4,7 +4,7 @@ import { logger } from './logger';
 export type ErrorContext = {
   action: string;
   userId?: string;
-  metadata?: Record<string, any>;
+  metadata?: Record<string, unknown>;
 };
 
 export class AppError extends Error {
@@ -66,11 +66,27 @@ export const handleInfo = (
  * Type-safe error message extraction utility
  * Use this instead of `error: any` in catch blocks
  */
-export const getErrorMessage = (error: unknown): string => {
-  if (error instanceof Error) return error.message;
-  if (typeof error === 'string') return error;
+export function getErrorMessage(error: unknown): string {
+  if (error instanceof Error) {
+    return error.message;
+  }
+  if (typeof error === 'string') {
+    return error;
+  }
   if (error && typeof error === 'object' && 'message' in error) {
     return String(error.message);
   }
   return 'An unexpected error occurred';
-};
+}
+
+/**
+ * Type guard to check if error has a code property
+ */
+export function hasErrorCode(error: unknown): error is { code: string } {
+  return (
+    error !== null &&
+    typeof error === 'object' &&
+    'code' in error &&
+    typeof (error as { code: unknown }).code === 'string'
+  );
+}