fix: proper TypeScript type assertion for error object

- Use type assertion to define error object structure
- Use optional chaining for safe property access
- Maintain all error handling functionality

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

web/src/pages/SettingsPage.tsx

@@ -227,11 +227,12 @@ function SettingsForm({ me, onBack }: { me: MemberRead; onBack: () => void }) {
                     } else if (err.message.includes('422')) {
                       errorMessage = 'Invalid image file. Please upload a valid image (JPG, PNG, etc.).';
                     }
-                  } else if (typeof err === 'object' && err !== null && 'status' in err && 'data' in err) {
+                  } else if (typeof err === 'object' && err !== null) {
                     // Try to extract more details from the error object
                     console.error("Error details:", JSON.stringify(err));
-                    if (err.status === 422 && err.data && 'detail' in err.data) {
-                      errorMessage = err.data.detail;
+                    const errorObj = err as { status?: number; data?: { detail?: string } };
+                    if (errorObj.status === 422 && errorObj.data?.detail) {
+                      errorMessage = errorObj.data.detail;
                     }
                   }