feat(node-modal): restore Parent Container selector for child types

Adds back the Parent Container selector in NodeModal, shown when:
- child type is lxc or vm (parents: proxmox/vm/lxc/docker_host)
- child type is docker_container (parents: docker_host/lxc/vm/proxmox)

Selector hidden when no valid candidate node exists on the canvas.
Centralizes the parent-type allowlist in getValidParentTypes
(shared with the virtual-edge auto-parent helper).

ha-relevant: yes

frontend/src/App.tsx

@@ -550,6 +550,7 @@ export default function App() {
           onClose={() => setAddNodeOpen(false)}
           onSubmit={handleAddNode}
           title="Add Node"
+          parentCandidates={nodes.map((n) => ({ id: n.id, label: n.data.label ?? n.id, type: n.data.type }))}
         />
 
         {/* key forces re-mount when editing a different node, resetting form state */}
@@ -560,6 +561,8 @@ export default function App() {
           onSubmit={handleUpdateNode}
           initial={editNode?.data}
           title="Edit Node"
+          parentCandidates={nodes.map((n) => ({ id: n.id, label: n.data.label ?? n.id, type: n.data.type }))}
+          currentNodeId={editNodeId ?? undefined}
         />
 
         <EdgeModal

frontend/src/components/modals/NodeModal.tsx

@@ -11,6 +11,7 @@ import { resolveNodeColors } from '@/utils/nodeColors'
 import { ICON_REGISTRY, ICON_CATEGORIES, NODE_TYPE_DEFAULT_ICONS, isBrandIconKey, brandIconSlug, brandIconUrl } from '@/utils/nodeIcons'
 import { BrandIconPicker } from './BrandIconPicker'
 import { MIN_BOTTOM_HANDLES, MAX_BOTTOM_HANDLES, clampBottomHandles } from '@/utils/handleUtils'
+import { getValidParentTypes } from '@/utils/virtualEdgeParent'
 
 const NODE_TYPE_GROUPS: { label: string; types: NodeType[] }[] = [
   { label: 'Hardware',       types: ['isp', 'router', 'firewall', 'switch', 'server', 'nas', 'ap', 'printer'] },
@@ -48,17 +49,25 @@ const DEFAULT_DATA: Partial<NodeData> = {
   custom_icon: undefined,
 }
 
+interface ParentCandidate {
+  id: string
+  label: string
+  type: NodeType
+}
+
 interface NodeModalProps {
   open: boolean
   onClose: () => void
   onSubmit: (data: Partial<NodeData>) => void
   initial?: Partial<NodeData>
   title?: string
+  parentCandidates?: ParentCandidate[]
+  currentNodeId?: string
 }
 
 // NodeModal is always mounted with a key that changes on open/edit, so useState
 // initial value is enough - no need for a reset effect.
-export function NodeModal({ open, onClose, onSubmit, initial, title = 'Add Node' }: NodeModalProps) {
+export function NodeModal({ open, onClose, onSubmit, initial, title = 'Add Node', parentCandidates = [], currentNodeId }: NodeModalProps) {
   const merged = { ...DEFAULT_DATA, ...initial }
   if (ZIGBEE_TYPES.includes((merged.type ?? '') as NodeType)) merged.check_method = 'none'
   const [form, setForm] = useState<Partial<NodeData>>(merged)
@@ -320,6 +329,40 @@ export function NodeModal({ open, onClose, onSubmit, initial, title = 'Add Node'
               </div>
             )}
 
+            {/* Parent Container */}
+            {(() => {
+              const childType = (form.type ?? 'generic') as NodeType
+              const validParentTypes = getValidParentTypes(childType)
+              if (validParentTypes.length === 0) return null
+              const validParents = parentCandidates.filter(
+                (n) => n.id !== currentNodeId && validParentTypes.includes(n.type),
+              )
+              if (validParents.length === 0) return null
+              return (
+                <div className="flex flex-col gap-1.5 col-span-2">
+                  <Label className="text-xs text-muted-foreground">Parent Container</Label>
+                  <Select
+                    value={form.parent_id ?? 'none'}
+                    onValueChange={(v) => set('parent_id', v === 'none' ? undefined : v)}
+                  >
+                    <SelectTrigger className={`bg-[#21262d] border-[#30363d] text-sm h-8 cursor-pointer ${modalStyles['modal-interactive']} ${modalStyles['modal-radius']}`} aria-label="Parent container selector">
+                      <SelectValue>
+                        {form.parent_id
+                          ? (validParents.find((n) => n.id === form.parent_id)?.label ?? 'None')
+                          : 'None'}
+                      </SelectValue>
+                    </SelectTrigger>
+                    <SelectContent className="bg-[#21262d] border-[#30363d]">
+                      <SelectItem value="none" className="text-sm">None</SelectItem>
+                      {validParents.map((n) => (
+                        <SelectItem key={n.id} value={n.id} className="text-sm">{n.label}</SelectItem>
+                      ))}
+                    </SelectContent>
+                  </Select>
+                </div>
+              )
+            })()}
+
             {/* Container mode */}
             {CONTAINER_MODE_TYPES.includes((form.type ?? 'generic') as NodeType) && (
               <div className="flex items-center justify-between col-span-2 py-1">

frontend/src/components/modals/__tests__/NodeModal.test.tsx

@@ -311,18 +311,48 @@ describe('NodeModal', () => {
     expect(screen.queryByText('Reset to defaults')).toBeNull()
   })
 
-  // ── Parent Container selector removed ────────────────────────────────
+  // ── Parent Container selector ─────────────────────────────────────────
 
-  it('does not render the Parent Container selector', () => {
-    renderModal({ initial: BASE })
+  it('does not render Parent Container for non-child types', () => {
+    renderModal({
+      initial: BASE,
+      parentCandidates: [{ id: 'p1', label: 'Proxmox', type: 'proxmox' }],
+    })
     expect(screen.queryByText('Parent Container')).toBeNull()
   })
 
-  it('does not render Parent Container for docker_container either', () => {
-    renderModal({ initial: { ...BASE, type: 'docker_container' } })
+  it('does not render Parent Container when no valid candidates exist', () => {
+    renderModal({
+      initial: { ...BASE, type: 'docker_container' },
+      parentCandidates: [],
+    })
     expect(screen.queryByText('Parent Container')).toBeNull()
   })
 
+  it('renders Parent Container for docker_container when docker_host candidate exists', () => {
+    renderModal({
+      initial: { ...BASE, type: 'docker_container' },
+      parentCandidates: [{ id: 'dh1', label: 'Docker Host', type: 'docker_host' }],
+    })
+    expect(screen.getByText('Parent Container')).toBeDefined()
+  })
+
+  it('renders Parent Container for docker_container when only an LXC candidate exists', () => {
+    renderModal({
+      initial: { ...BASE, type: 'docker_container' },
+      parentCandidates: [{ id: 'lxc1', label: 'My LXC', type: 'lxc' }],
+    })
+    expect(screen.getByText('Parent Container')).toBeDefined()
+  })
+
+  it('renders Parent Container for lxc when proxmox candidate exists', () => {
+    renderModal({
+      initial: { ...BASE, type: 'lxc' },
+      parentCandidates: [{ id: 'px1', label: 'PVE', type: 'proxmox' }],
+    })
+    expect(screen.getByText('Parent Container')).toBeDefined()
+  })
+
   // ── Appearance ────────────────────────────────────────────────────────
 
   it('renders 3 color swatch labels (border, background, icon)', () => {

frontend/src/utils/virtualEdgeParent.ts

@@ -15,6 +15,16 @@ export interface ParentAssignment {
   parentId: string
 }
 
+export function getValidParentTypes(childType: NodeType): NodeType[] {
+  if (childType === 'lxc' || childType === 'vm') {
+    return ['proxmox', 'vm', 'lxc', 'docker_host']
+  }
+  if (childType === 'docker_container') {
+    return ['docker_host', 'lxc', 'vm', 'proxmox']
+  }
+  return []
+}
+
 export function resolveVirtualEdgeParent(
   source: VirtualEdgeEndpoint,
   target: VirtualEdgeEndpoint,