Add Prettier for TypeScript formatting

- Install prettier
- Configure .prettierrc.json and .prettierignore
- Add npm scripts: format, format:check
- Add Makefile target: format-frontend
- Format all frontend files

frontend/app/api.ts

@@ -16,26 +16,23 @@ export class ApiError extends Error {
   }
 }
 
-async function request<T>(
-  endpoint: string,
-  options: RequestInit = {}
-): Promise<T> {
+async function request<T>(endpoint: string, options: RequestInit = {}): Promise<T> {
   const url = `${API_URL}${endpoint}`;
-  
+
   const headers: Record<string, string> = {
     ...(options.headers as Record<string, string>),
   };
-  
+
   if (options.body && typeof options.body === "string") {
     headers["Content-Type"] = "application/json";
   }
-  
+
   const res = await fetch(url, {
     ...options,
     headers,
     credentials: "include",
   });
-  
+
   if (!res.ok) {
     let data: unknown;
     try {
@@ -43,13 +40,9 @@ async function request<T>(
     } catch {
       // Response wasn't JSON
     }
-    throw new ApiError(
-      `Request failed: ${res.status}`,
-      res.status,
-      data
-    );
+    throw new ApiError(`Request failed: ${res.status}`, res.status, data);
   }
-  
+
   return res.json();
 }
 
@@ -57,14 +50,14 @@ export const api = {
   get<T>(endpoint: string): Promise<T> {
     return request<T>(endpoint);
   },
-  
+
   post<T>(endpoint: string, body?: unknown): Promise<T> {
     return request<T>(endpoint, {
       method: "POST",
       body: body ? JSON.stringify(body) : undefined,
     });
   },
-  
+
   put<T>(endpoint: string, body?: unknown): Promise<T> {
     return request<T>(endpoint, {
       method: "PUT",
@@ -72,4 +65,3 @@ export const api = {
     });
   },
 };
-