fix(words): normalize handles image blocks + 3 image tests (F3.11 partial)

normalizeBlock had no case for type='image' — image blocks coming from
parseWordsMarkdown / parseWordsHtml were silently dropped at the
default branch. Now:

- normalize.ts case 'image': validates src (non-empty + sanitizeWordsUrl),
  passes through alt / caption / width (numeric) / height (numeric) /
  align (validated via isWordsImageAlign) / status ('pending' | 'error').
- normalize.ts imports createImage + isWordsImageAlign from the
  extension.

Image-extension cast widened with `as unknown as ErasedFactory` because
WordsImageBlock (no `children` field) doesn't satisfy the contract's
node shape strictly; the double-cast is the same pattern table-extension
already uses for typed factories.

3 new engine tests cover the F3 happy path:
- parses a block-level markdown image (![alt](src "caption") on its
  own line yields a type:'image' block)
- round-trips an image through markdown (serialize → parse → matches)
- round-trips an image through HTML (figure>img+figcaption → ImageBlock
  → serialize back)

85/85 engine tests pass (was 82; +3 image tests).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/uix/soma/components/words/engine/engine.test.ts

@@ -892,6 +892,45 @@ describe('Words engine', () => {
 		});
 	});
 
+	it('parses a block-level markdown image', () => {
+		const md = '# Title\n\n![A cat](https://example.com/cat.jpg "Cute kitten")\n\nAfter.';
+		const doc = parseWordsMarkdown(md);
+		expect(doc.children).toHaveLength(3);
+		expect(doc.children[0]).toMatchObject({ type: 'heading' });
+		expect(doc.children[1]).toMatchObject({
+			type: 'image',
+			src: 'https://example.com/cat.jpg',
+			alt: 'A cat',
+			caption: 'Cute kitten'
+		});
+		expect(doc.children[2]).toMatchObject({ type: 'paragraph' });
+	});
+
+	it('round-trips an image through markdown', () => {
+		const original = parseWordsMarkdown('![alt](https://example.com/x.png)');
+		const back = parseWordsMarkdown(serializeWordsMarkdown(original));
+		expect(back.children[0]).toMatchObject({
+			type: 'image',
+			src: 'https://example.com/x.png',
+			alt: 'alt'
+		});
+	});
+
+	it('round-trips an image through HTML', () => {
+		const html = '<figure><img src="https://example.com/x.png" alt="alt"><figcaption>cap</figcaption></figure>';
+		const doc = parseWordsHtml(html);
+		expect(doc.children[0]).toMatchObject({
+			type: 'image',
+			src: 'https://example.com/x.png',
+			alt: 'alt',
+			caption: 'cap'
+		});
+		const out = serializeWordsHtml(doc);
+		expect(out).toContain('<figure');
+		expect(out).toContain('<img src="https://example.com/x.png"');
+		expect(out).toContain('<figcaption>cap</figcaption>');
+	});
+
 	it('edits table rows and columns from the active cell', () => {
 		let state = createWordsState(
 			documentWithChildren([

src/uix/soma/components/words/engine/normalize.ts

@@ -30,6 +30,7 @@ import {
 	type WordsTableCell,
 	type WordsTableRow
 } from './document';
+import { createImage, isWordsImageAlign } from '../extensions/image';
 
 export type WordsNormalizeReason =
 	| 'invalid-document'
@@ -143,6 +144,35 @@ function normalizeBlock(
 				compact: source.compact === true
 			});
 		}
+		case 'image': {
+			const src = typeof source.src === 'string' ? source.src : '';
+			if (!src) {
+				issues.push({ reason: 'invalid-block', path, value: 'image missing src' });
+				return undefined;
+			}
+			const sanitized = sanitizeWordsUrl(src);
+			if (!sanitized) {
+				issues.push({ reason: 'unsafe-url', path, value: src });
+				return undefined;
+			}
+			return createImage(sanitized, {
+				alt: typeof source.alt === 'string' ? source.alt : undefined,
+				caption: typeof source.caption === 'string' ? source.caption : undefined,
+				width:
+					typeof source.width === 'number' && Number.isFinite(source.width)
+						? source.width
+						: undefined,
+				height:
+					typeof source.height === 'number' && Number.isFinite(source.height)
+						? source.height
+						: undefined,
+				align: isWordsImageAlign(source.align) ? source.align : undefined,
+				status:
+					source.status === 'pending' || source.status === 'error'
+						? source.status
+						: undefined
+			});
+		}
 		default:
 			issues.push({ reason: 'invalid-block', path, value: source.type });
 			return undefined;

src/uix/soma/components/words/extensions/image/image-extension.ts

@@ -24,7 +24,9 @@ import { createImage } from './factories';
 type ErasedFactory = (...args: ReadonlyArray<unknown>) => WordsExtensionNode;
 
 const imageFactory = ((...args: ReadonlyArray<unknown>) =>
-	createImage(...(args as Parameters<typeof createImage>))) as ErasedFactory;
+	createImage(
+		...(args as Parameters<typeof createImage>)
+	)) as unknown as ErasedFactory;
 
 export const imageExtension: WordsExtension = {
 	name: 'image',