Show last update time on the story page

The story page already showed last check time. Add last update time
next to it, from the existing last_changed field.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

bindery/static/js/story.js

@@ -155,6 +155,7 @@ export function storyPage(main, { storyId }, config) {
           story.status && badge(story.status),
           ` ${story.message || ''}`,
           story.last_checked && h('span', { class: 'last-check' }, ` Last check ${fmtDate(story.last_checked)}.`),
+          story.last_changed && h('span', { class: 'last-update' }, ` Last update ${fmtDate(story.last_changed)}.`),
         ),
         details.library_error && h('p', { class: 'error' }, `CWA: ${details.library_error}`),
         holdNotice(),

bindery/static/style.css

@@ -466,6 +466,7 @@ label:has(> input[type='radio']) {
 
 .byline,
 .last-check,
+.last-update,
 .story-site,
 .field-default,
 small,