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/fields/PartialField.vue

@@ -0,0 +1,31 @@
+<script setup lang="ts">
+import { t } from '../../../app/i18n'
+import PartialHost from '../../partial/PartialHost.vue'
+import ExtensionFailure from '../../ui/ExtensionFailure.vue'
+import type { FieldControlProps } from '../control'
+
+// A `type: partial` form row (D-09; UI-SPEC S2): the controller partial
+// named by `path`, rendered on create (no record) and update (?id=). It holds
+// no value. The row's visible label, when declared, names the group. A form
+// without a controller (a settings page) has no partial route to call.
+const props = defineProps<FieldControlProps>()
+</script>
+
+<template>
+  <div
+    :id="controlId"
+    role="group"
+    data-partial-field
+    :aria-labelledby="props.field.label ? `${controlId}-label` : undefined"
+    :aria-describedby="describedBy || undefined"
+  >
+    <PartialHost
+      v-if="source"
+      variant="field"
+      :source="source"
+      :name="props.field.path || props.field.name"
+      :record-id="recordId ?? null"
+    />
+    <ExtensionFailure v-else data-partial-failed :text="t('backend::lang.extension.partial_failed')" />
+  </div>
+</template>

admin/src/components/form/fields/WidgetField.vue

@@ -162,7 +162,7 @@ onBeforeUnmount(() => {
     :id="controlId"
     role="group"
     data-widget-host
-    :aria-labelledby="`${controlId}-label`"
+    :aria-labelledby="field.label ? `${controlId}-label` : undefined"
     :aria-describedby="describedBy || undefined"
     :aria-busy="status === 'loading' ? 'true' : undefined"
     class="flex min-h-input items-center"