feat(settings): move Hide IP toggle into Settings modal, persist it

Hide-IP was a sidebar button held only in memory, so it reset on reload.
Moved it into the Settings modal Canvas section and persist it to
localStorage (new ipDisplay util); the canvas store now seeds hideIp from
storage and writes through on toggleHideIp/setHideIp. Settings is now also
reachable in standalone (no-backend) builds, with the backend-only status
interval guarded so the modal still works there.

ha-relevant: yes

frontend/src/stores/__tests__/canvasStore.test.ts

@@ -800,6 +800,26 @@ describe('canvasStore', () => {
     expect(useCanvasStore.getState().nodes).toHaveLength(1)
   })
 
+  // --- Hide IP preference (persisted to localStorage) ---
+
+  it('toggleHideIp flips the flag and persists it', () => {
+    localStorage.removeItem('homelable.hideIp')
+    useCanvasStore.setState({ hideIp: false })
+    useCanvasStore.getState().toggleHideIp()
+    expect(useCanvasStore.getState().hideIp).toBe(true)
+    expect(localStorage.getItem('homelable.hideIp')).toBe('true')
+    useCanvasStore.getState().toggleHideIp()
+    expect(useCanvasStore.getState().hideIp).toBe(false)
+    expect(localStorage.getItem('homelable.hideIp')).toBe('false')
+  })
+
+  it('setHideIp sets the flag and persists it', () => {
+    localStorage.removeItem('homelable.hideIp')
+    useCanvasStore.getState().setHideIp(true)
+    expect(useCanvasStore.getState().hideIp).toBe(true)
+    expect(localStorage.getItem('homelable.hideIp')).toBe('true')
+  })
+
   // --- Node resizing (width / height) ---
 
   it('addNode preserves explicit width and height', () => {