fix(primitives): eslint/tsconfig migration, asChild refactor, type fixes

- Migrate to eslint flat config + composite tsconfig.
- Complete the asChild→as="template" refactor (remove asChild prop + :as-child
  bindings across components, matching Primitive's slot model).
- Fix test type errors and source type-safety (useGraceArea hull/point math,
  FocusScope/util ref typing).

Note: ~53 vue-tsc errors remain (HTML attr/event passthrough typing on
transparent wrapper components + a couple of duplicate-export naming
collisions) — not gated by CI (build/lint/test green); pending a
component-attribute-typing design decision.

vue/primitives/src/editable/__test__/Editable.test.ts

@@ -0,0 +1,172 @@
+import {
+  EditableArea,
+  EditableCancelTrigger,
+  EditableEditTrigger,
+  EditableInput,
+  EditablePreview,
+  EditableRoot,
+  EditableSubmitTrigger,
+} from '../index';
+import { defineComponent, h, nextTick, ref } from 'vue';
+import { describe, expect, it } from 'vitest';
+import { mount } from '@vue/test-utils';
+
+function createEditable(rootProps: Record<string, unknown> = {}) {
+  return mount(
+    defineComponent({
+      setup() {
+        return () => h(
+          EditableRoot,
+          rootProps,
+          {
+            default: () => h(EditableArea, null, {
+              default: () => [
+                h(EditablePreview),
+                h(EditableInput),
+                h(EditableEditTrigger),
+                h(EditableSubmitTrigger),
+                h(EditableCancelTrigger),
+              ],
+            }),
+          },
+        );
+      },
+    }),
+    { attachTo: document.body },
+  );
+}
+
+function press(el: Element, key: string) {
+  el.dispatchEvent(new KeyboardEvent('keydown', { key, bubbles: true, cancelable: true }));
+}
+
+describe('Editable', () => {
+  it('renders preview with default placeholder when empty', () => {
+    const w = createEditable({ placeholder: 'Click to edit' });
+    const preview = w.find('span');
+    expect(preview.text()).toBe('Click to edit');
+    expect(preview.attributes('data-placeholder-shown')).toBe('');
+    w.unmount();
+  });
+
+  it('renders model value in preview', () => {
+    const w = createEditable({ modelValue: 'Hello' });
+    expect(w.find('span').text()).toBe('Hello');
+    w.unmount();
+  });
+
+  it('focus activation enters edit mode', async () => {
+    const w = createEditable({ defaultValue: 'X', activationMode: 'focus' });
+    await w.find('span').trigger('focusin');
+    await nextTick();
+    const input = w.find('input').element as HTMLInputElement;
+    expect(input.hidden).toBe(false);
+    expect((w.find('span').element as HTMLElement).hidden).toBe(true);
+    w.unmount();
+  });
+
+  it('dblclick activation enters edit mode only on dblclick', async () => {
+    const w = createEditable({ activationMode: 'dblclick' });
+    await w.find('span').trigger('focusin');
+    await nextTick();
+    expect((w.find('input').element as HTMLInputElement).hidden).toBe(true);
+    await w.find('span').trigger('dblclick');
+    await nextTick();
+    expect((w.find('input').element as HTMLInputElement).hidden).toBe(false);
+    w.unmount();
+  });
+
+  it('edit trigger switches to edit mode', async () => {
+    const w = createEditable({ activationMode: 'none' });
+    const buttons = w.findAll('button');
+    const editBtn = buttons.find(b => b.attributes('aria-label') === 'edit')!;
+    await editBtn.trigger('click');
+    await nextTick();
+    expect((w.find('input').element as HTMLInputElement).hidden).toBe(false);
+    w.unmount();
+  });
+
+  it('Enter submits when submitMode includes enter', async () => {
+    const value = ref('initial');
+    const w = mount(
+      defineComponent({
+        setup() {
+          return () => h(
+            EditableRoot,
+            {
+              modelValue: value.value,
+              submitMode: 'enter',
+              startWithEditMode: true,
+              'onUpdate:modelValue': (v: string) => (value.value = v),
+            },
+            {
+              default: () => h(EditableArea, null, {
+                default: () => [h(EditablePreview), h(EditableInput)],
+              }),
+            },
+          );
+        },
+      }),
+      { attachTo: document.body },
+    );
+    await nextTick();
+    const input = w.find('input');
+    (input.element as HTMLInputElement).value = 'changed';
+    await input.trigger('input');
+    press(input.element, 'Enter');
+    await nextTick();
+    expect(value.value).toBe('changed');
+    w.unmount();
+  });
+
+  it('Escape cancels and restores model value', async () => {
+    const w = createEditable({ defaultValue: 'orig', submitMode: 'enter' });
+    const editBtn = w.findAll('button').find(b => b.attributes('aria-label') === 'edit')!;
+    await editBtn.trigger('click');
+    await nextTick();
+    const input = w.find('input');
+    (input.element as HTMLInputElement).value = 'new';
+    await input.trigger('input');
+    press(input.element, 'Escape');
+    await nextTick();
+    expect(w.find('span').text()).toBe('orig');
+    w.unmount();
+  });
+
+  it('submit trigger emits submit', async () => {
+    const w = createEditable({ defaultValue: 'v1', startWithEditMode: true });
+    await nextTick();
+    const input = w.find('input');
+    (input.element as HTMLInputElement).value = 'v2';
+    await input.trigger('input');
+    const submitBtn = w.findAll('button').find(b => b.attributes('aria-label') === 'submit')!;
+    await submitBtn.trigger('click');
+    await nextTick();
+    const root = w.findComponent(EditableRoot);
+    expect(root.emitted('update:modelValue')?.at(-1)).toEqual(['v2']);
+    expect(root.emitted('submit')?.at(-1)).toEqual(['v2']);
+    w.unmount();
+  });
+
+  it('cancel trigger reverts draft', async () => {
+    const w = createEditable({ defaultValue: 'v1', startWithEditMode: true });
+    await nextTick();
+    const input = w.find('input');
+    (input.element as HTMLInputElement).value = 'draft';
+    await input.trigger('input');
+    const cancelBtn = w.findAll('button').find(b => b.attributes('aria-label') === 'cancel')!;
+    await cancelBtn.trigger('click');
+    await nextTick();
+    expect(w.find('span').text()).toBe('v1');
+    expect(w.findComponent(EditableRoot).emitted('update:modelValue')).toBeUndefined();
+    w.unmount();
+  });
+
+  it('disabled blocks edit activation', async () => {
+    const w = createEditable({ defaultValue: 'v', disabled: true });
+    await w.find('span').trigger('focusin');
+    await nextTick();
+    expect((w.find('input').element as HTMLInputElement).hidden).toBe(true);
+    w.unmount();
+  });
+});