feat: add internationalization message handling in messages.ts

frontend/src/lib/i18n/messages.ts

@@ -1,10 +1,10 @@
 import * as generatedMessages from '$lib/paraglide/messages';
 
-const normalizedMessageKeyCache = new Map();
-const generatedMessagesAny = /** @type {Record<string, any>} */ (generatedMessages);
+const normalizedMessageKeyCache = new Map<string, string>();
+const generatedMessagesAny: Record<string, unknown> = generatedMessages;
 
-export const m = new Proxy({}, {
-	get(_target, property) {
+export const m = new Proxy({} as typeof generatedMessages, {
+	get(_target, property: string | symbol) {
 		if (typeof property !== 'string') {
 			return undefined;
 		}
@@ -36,4 +36,4 @@ export const m = new Proxy({}, {
 
 		return generatedMessagesAny[property];
 	}
-});
+}) as typeof generatedMessages;