fix: hide is_a/Is A from editable properties (already shown as TypeRow)

The is_a frontmatter key was appearing both as the TypeRow badge and
as a regular editable property. Added both 'is_a' and 'Is A' variants
to SKIP_KEYS to prevent duplication (snake_case used in mock data,
space-separated used in real vault YAML).

Added test verifying is_a is skipped when TypeRow is present.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/DynamicPropertiesPanel.test.tsx

@@ -128,6 +128,23 @@ describe('DynamicPropertiesPanel', () => {
     expect(screen.getByText('cadence')).toBeInTheDocument()
   })
 
+  it('skips is_a key since it is shown via TypeRow', () => {
+    render(
+      <DynamicPropertiesPanel
+        entry={makeEntry({ isA: 'Project' })}
+        content=""
+        frontmatter={{ is_a: 'Project', Status: 'Active' }}
+      />
+    )
+    // Type is shown via TypeRow, is_a should NOT appear as a separate editable property
+    const editableRows = screen.getAllByTestId('editable-property')
+    const editableLabels = editableRows.map(row => row.querySelector('span')?.textContent?.replace('×', '').trim())
+    expect(editableLabels).not.toContain('is_a')
+    // But Type row should still show
+    expect(screen.getByText('Type')).toBeInTheDocument()
+    expect(screen.getByText('Project')).toBeInTheDocument()
+  })
+
   it('renders boolean property as toggle', () => {
     render(
       <DynamicPropertiesPanel

src/components/DynamicPropertiesPanel.tsx

@@ -28,7 +28,7 @@ export const RELATIONSHIP_KEYS = new Set([
 ])
 
 // Keys to skip showing in Properties
-const SKIP_KEYS = new Set(['aliases', 'notion_id', 'workspace'])
+const SKIP_KEYS = new Set(['aliases', 'notion_id', 'workspace', 'is_a', 'Is A'])
 
 // eslint-disable-next-line react-refresh/only-export-components -- utility co-located with component
 export function containsWikilinks(value: FrontmatterValue): boolean {