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/src/blocks/heading.ts

@@ -0,0 +1,18 @@
+import { defineBlock } from '../registry';
+
+const LEVELS = [1, 2, 3, 4, 5, 6] as const;
+
+export const heading = defineBlock({
+  type: 'heading',
+  spec: {
+    content: { kind: 'text' },
+    group: 'block',
+    attrs: {
+      level: { default: 1, validate: value => typeof value === 'number' && value >= 1 && value <= 6 },
+    },
+    toDOM: node => [`h${node.attrs['level'] ?? 1}`, 0],
+    parseDOM: LEVELS.map(level => ({ tag: `h${level}`, attrs: { level } })),
+  },
+  inputRules: LEVELS.map(level => ({ match: new RegExp(`^#{${level}}\\s$`), attrs: { level } })),
+  meta: { title: 'Heading', icon: 'heading', keywords: ['heading', 'title', 'h1', 'h2', 'h3'], group: 'basic' },
+});