fix: address code review feedback - disable field type selector, simplify width validation, improve test assertions

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

packages/plugin-designer/src/ViewDesigner.tsx

@@ -754,12 +754,8 @@ export function ViewDesigner({
                       <label className="text-xs text-muted-foreground">Field Type</label>
                       <select
                         value={availableFields.find((f) => f.name === columns[selectedColumnIndex].field)?.type ?? 'text'}
-                        onChange={(e) => {
-                          if (readOnly) return;
-                          // Field type is informational — stored on the availableField, not the column
-                        }}
-                        className="w-full px-2 py-1 text-sm border rounded bg-background mt-1"
-                        disabled={readOnly}
+                        disabled
+                        className="w-full px-2 py-1 text-sm border rounded bg-muted/50 mt-1"
                         data-testid="column-field-type"
                       >
                         {DESIGNER_FIELD_TYPES.map((ft) => (
@@ -780,7 +776,7 @@ export function ViewDesigner({
                           const val = e.target.value;
                           if (val === '' || val === 'auto') {
                             pushState({
-                              columns: columns.map((c, i) => (i === idx ? { ...c, width: val || undefined } : c)),
+                              columns: columns.map((c, i) => (i === idx ? { ...c, width: val === 'auto' ? 'auto' : undefined } : c)),
                             });
                             return;
                           }

packages/plugin-designer/src/__tests__/DataModelDesigner.test.tsx

@@ -192,14 +192,17 @@ describe('DataModelDesigner', () => {
       const onChange = vi.fn();
       render(<DataModelDesigner entities={MOCK_ENTITIES} onEntitiesChange={onChange} />);
 
+      const callCountBefore = onChange.mock.calls.length;
+
       const label = screen.getByTestId('entity-label-entity-1');
       fireEvent.doubleClick(label);
 
       const input = screen.getByTestId('entity-label-input-entity-1');
       fireEvent.change(input, { target: { value: '   ' } });
       fireEvent.keyDown(input, { key: 'Enter' });
 
-      // Should not have committed (no onEntitiesChange beyond any prior calls)
+      // Should not have committed (no additional onEntitiesChange call)
+      expect(onChange.mock.calls.length).toBe(callCountBefore);
       // The input should be gone (editing cancelled)
       expect(screen.queryByTestId('entity-label-input-entity-1')).toBeNull();
     });