Fix learn dialog rendering, add lab publish/draft toggle, bump to v0.1.2

- learn/index.html: restructured dialogs inside section divs to fix scope
- learn/index.html: edit-article dialogs via flat articles list in modal blocks
- LearnController: sectionChoices for select options; secure article fetching
- ContentService: createArticlePlaced: new section adjacent to anchor section
- lab status: published = student-visible, draft = hidden
- lab toggle: click badge in labs list or button in lab header to switch status
- added badge-btn CSS class, removed inline styles
- removed all th:onclick with expressions → data-modal attributes
- footer v0.1.2

web/src/main/resources/static/css/app.css

@@ -136,6 +136,7 @@ a:hover { color: var(--c-text-link-hover); }
 .badge { display: inline-flex; align-items: center; border-radius: 9999px; padding: 0.125rem 0.625rem; font-size: 0.75rem; font-weight: 500; }
 .badge-ok { background: var(--c-badge-ok-bg); color: var(--c-badge-ok-text); }
 .badge-warn { background: var(--c-badge-warn-bg); color: var(--c-badge-warn-text); }
+.badge-btn { border: none; cursor: pointer; padding: 0.125rem 0.625rem; }
 
 /* Tables */
 table { width: 100%; font-size: 0.875rem; border-collapse: collapse; }