fix: remove incorrect headers parameter from API call

- Remove extra parameter that was causing TypeScript error
- Keep all other file size handling improvements

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

web/src/pages/SettingsPage.tsx

@@ -211,11 +211,7 @@ function SettingsForm({ me, onBack }: { me: MemberRead; onBack: () => void }) {
                   
                   console.log("Uploading file to /auth/me/avatar");
                   console.log("Final file size:", processedFile.size);
-                  const response = await api.post<MemberRead>('/auth/me/avatar', formData, {
-                    headers: {
-                      'Content-Type': 'multipart/form-data'
-                    }
-                  });
+                  const response = await api.post<MemberRead>('/auth/me/avatar', formData);
                   console.log("Upload response:", response);
                   
                   setAvatarUrl(response.avatar_url || '');