Add the web interface

Plain HTML, CSS and JavaScript modules, with no build step. Hash routes
and relative URLs make it work under any path. The job list is polled:
every 2 seconds while a job runs, and less often otherwise.

tests/js/revisions.test.mjs

@@ -0,0 +1,24 @@
+import assert from 'node:assert/strict';
+import { test } from 'node:test';
+import { Element, find, install, nodes, server, settle } from './flow-helpers.mjs';
+
+install();
+const { chapterPage } = await import('../../bindery/static/js/chapter.js');
+
+test('the revision in the book and the newest revision have no Delete button', async (t) => {
+  const backend = server(t);
+  backend.on('GET', 'jobs', []);
+  backend.on('GET', 'chapters/2/diff?', {
+    chapter: { id: 2, title: 'One', url: 'https://example.com/c/1', current_rev: 1 }, story_title: 'Story',
+    a: 1, b: 3, identical: false, html: '', changed: 1, added: 0, removed: 0,
+    revisions: [{ rev: 1, size: 100 }, { rev: 2, size: 100 }, { rev: 3, size: 100 }],
+  });
+  const main = new Element('main');
+  const cleanup = chapterPage(main, { storyId: '1', chapterId: '2' });
+  await settle();
+  cleanup?.();
+  const rows = nodes(main).filter((el) => el.tagName === 'tr').slice(1);
+  const badges = rows.map((row) => nodes(row.children[0]).filter((el) => el.tagName === 'span').map((el) => el.textContent));
+  assert.deepEqual(badges, [['in book'], [], ['newest']]);
+  assert.deepEqual(rows.map((row) => Boolean(find(row, 'button', 'Delete'))), [false, true, false]);
+});