fix: prevent 'Cannot read properties of undefined (reading '0')' errors (#385)

- Add proper array length checks before accessing error.errors[0]
- Secure error handling in App.tsx for both map loading and layer loading
- Fix unsafe array access in mapApi.ts error handler
- Prevent crashes when error.errors is undefined or empty array

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

app/src/App.tsx

@@ -117,7 +117,7 @@ function App() {
       setError(
         typeof error === 'string'
           ? error
-          : error?.errors?.[0]?.message ||
+          : (error?.errors?.length > 0 ? error.errors[0]?.message : null) ||
               error?.message ||
               'Failed to connect to the server. Please check your connection and try again.',
       )
@@ -158,7 +158,7 @@ function App() {
       setError(
         typeof error === 'string'
           ? error
-          : error?.errors?.[0]?.message ||
+          : (error?.errors?.length > 0 ? error.errors[0]?.message : null) ||
               error?.message ||
               'Failed to load map layers. Please check your permissions and try again.',
       )

app/src/api/mapApi.ts

@@ -26,7 +26,7 @@ export class mapApi {
       else return 'null'
     } catch (error: any) {
       console.log(error)
-      if (error.errors[0]?.message) throw error.errors[0].message
+      if (error.errors?.length > 0 && error.errors[0]?.message) throw error.errors[0].message
       else throw error
     }
   }