feat(writekit): rename @robonen/editor to @robonen/writekit

Rename the rich-text editor package and all Editor* exports to Writekit*;
remove the old vue/editor tree.

vue/writekit/playground/src/demos/RichTextDemo.vue

@@ -0,0 +1,33 @@
+<script setup lang="ts">
+import { computed, ref } from 'vue';
+import { WritekitBubbleMenu, WritekitContent, WritekitRoot, WritekitSlashMenu } from '@writekit';
+import { h, makeWritekit, p, t } from '../lib';
+import Toolbar from '../Toolbar.vue';
+
+const writekit = makeWritekit([
+  h(1, 'Welcome to the writekit'),
+  p([t('This paragraph mixes '), t('bold', 'bold'), t(', '), t('italic', 'italic'), t(', and '), t('both at once', 'bold', 'italic'), t('.')]),
+  p('Drag with the mouse across these two paragraphs — the selection spans both, just like Word. Use ↑/↓ to move between blocks and Shift+↑/↓ to extend across them.'),
+  p(''),
+  h(2, 'Editing'),
+  p('Press Enter to split a block. Press Backspace at the very start of a block to merge it into the previous one. Cmd/Ctrl+Z undoes, Cmd/Ctrl+Shift+Z redoes.'),
+]);
+
+const rev = ref(0);
+writekit.on('transaction', () => (rev.value += 1));
+const docJson = computed(() => (rev.value, JSON.stringify(writekit.state.doc, null, 2)));
+</script>
+
+<template>
+  <section>
+    <h2>Rich text</h2>
+    <p class="hint">Mixed marks, headings, an empty block (placeholder), cross-block selection &amp; navigation.</p>
+    <Toolbar :writekit="writekit" />
+    <WritekitRoot :writekit="writekit" autofocus class="writekit">
+      <WritekitContent />
+      <WritekitBubbleMenu />
+      <WritekitSlashMenu />
+    </WritekitRoot>
+    <details><summary>document JSON</summary><pre>{{ docJson }}</pre></details>
+  </section>
+</template>