feat(10.1-02): render header and form partials through an allowlisted node renderer

- partialNodes rebuilds the server node tree with h() under the server's tag, attribute and URL lists
- PartialHost owns the skeleton, empty and failure states and keeps nodes visible on refetch
- type: partial is a valueless group-labelled field rendered on create and update
- ListView shows headerPartial above the list card and refetches it after bulk delete
- summer-partial and summer-stats style kit in main.css, documented in the cabana README; dist rebuilt

admin/src/components/form/registry.ts

@@ -4,12 +4,13 @@
 // is registered like any control but holds no form value: it edits its
 // relation through its own endpoints and renders only on an existing record.
 // Phase 10.1 adds the plugin extension types: a widget mounts a plugin custom
-// element (D-04, D-09). It holds no form value either, but it renders on
-// create and update.
+// element (D-04, D-09) and a partial renders a server template (D-17). They
+// hold no form value either, but they render on create and update.
 import type { Component } from 'vue'
 import CheckboxField from './fields/CheckboxField.vue'
 import DropdownField from './fields/DropdownField.vue'
 import NumberField from './fields/NumberField.vue'
+import PartialField from './fields/PartialField.vue'
 import RelationManager from '../relation/RelationManager.vue'
 import RelationField from './fields/RelationField.vue'
 import SwitchField from './fields/SwitchField.vue'
@@ -37,6 +38,7 @@ const renderers = new Map<string, Component>([
   ['relation', RelationField],
   [RELATION_MANAGER, RelationManager],
   ['widget', WidgetField],
+  ['partial', PartialField],
 ])
 
 /** Types whose control shows the label itself (toggle cards, relation manager). */
@@ -49,13 +51,13 @@ const selfLabelled = new Set<string>(['switch', 'checkbox', RELATION_MANAGER])
 const recordBound = new Set<string>([RELATION_MANAGER])
 
 /** Types that hold no form value: never part of the save body (D-09). */
-const valueless = new Set<string>([RELATION_MANAGER, 'widget'])
+const valueless = new Set<string>([RELATION_MANAGER, 'widget', 'partial'])
 
 /**
  * Types whose control is a group rather than one focusable element: the
  * visible label is a span the group points at, not a label for an input.
  */
-const groupLabelledTypes = new Set<string>(['widget'])
+const groupLabelledTypes = new Set<string>(['widget', 'partial'])
 
 export function rendererFor(type: string): Component {
   return renderers.get(type) ?? UnsupportedField
@@ -75,7 +77,10 @@ export function ownsLabel(type: string): boolean {
   return selfLabelled.has(type)
 }
 
-/** Whether a field type's label labels a group (widget) instead of a control. */
+/**
+ * Whether a field type's label names a group (widget, partial) instead of a
+ * control. Such a row shows no label row when the field declares no label.
+ */
 export function groupLabelled(type: string): boolean {
   return groupLabelledTypes.has(type)
 }