feat(web): chat + llmAdmin api clients with FormData support

web/src/api/client.ts

@@ -21,10 +21,11 @@ export function configure(opts: {
 }
 
 export async function request<T>(path: string, opts: RequestOptions = {}): Promise<T> {
+  const isForm = opts.body instanceof FormData
   const headers: Record<string, string> = {
-    'Content-Type': 'application/json',
     'X-Client-Request-ID': crypto.randomUUID(),
   }
+  if (!isForm) headers['Content-Type'] = 'application/json'
   const token = authTokenProvider()
   if (token) headers['Authorization'] = `Bearer ${token}`
 
@@ -39,10 +40,16 @@ export async function request<T>(path: string, opts: RequestOptions = {}): Promi
   }
 
   try {
+    const body =
+      opts.body === undefined
+        ? undefined
+        : isForm
+          ? (opts.body as FormData)
+          : JSON.stringify(opts.body)
     const resp = await fetch(BASE + path, {
       method: opts.method || 'GET',
       headers,
-      body: opts.body !== undefined ? JSON.stringify(opts.body) : undefined,
+      body,
       signal: controller.signal,
     })