Add rich text editor to assignment body field

Replaces the plain textarea with a contenteditable div + full toolbar
(bold, italic, underline, H2/H3, paragraph, bullet/numbered lists, link,
YouTube embed) — same as the lesson editor.

Toolbar buttons use mousedown+preventDefault so selection is preserved
when clicking format buttons. Both editors share the same button wiring
via closest('.rte-group') rather than hardcoded element IDs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

public/admin.html

@@ -181,7 +181,7 @@
             <p id="import-status" class="hint"></p>
           </div>
 
-          <div id="ie-field-lesson" class="ie-field">
+          <div id="ie-field-lesson" class="ie-field rte-group">
             <div class="rte-label">Lesson content</div>
             <div class="rte-toolbar">
               <button type="button" class="rte-btn" data-cmd="bold" title="Bold"><b>B</b></button>
@@ -195,16 +195,33 @@
               <button type="button" class="rte-btn" data-cmd="insertUnorderedList" title="Bullet list">• List</button>
               <button type="button" class="rte-btn" data-cmd="insertOrderedList" title="Numbered list">1. List</button>
               <span class="rte-sep"></span>
-              <button type="button" class="rte-btn" id="rte-link-btn" title="Add link">🔗 Link</button>
-              <button type="button" class="rte-btn" id="rte-youtube-btn" title="Embed YouTube">▶ YouTube</button>
+              <button type="button" class="rte-btn rte-link-btn" title="Add link">🔗 Link</button>
+              <button type="button" class="rte-btn rte-youtube-btn" title="Embed YouTube">▶ YouTube</button>
             </div>
             <div id="ie-body-lesson" class="rte-editor lesson-body" contenteditable="true"
               data-placeholder="Weather is what the sky and air are doing right now.&#10;Add images, YouTube embeds, and more."></div>
           </div>
 
-          <div id="ie-field-assignment" class="ie-field">
-            <label>Instructions <textarea id="ie-body-assignment" rows="5" placeholder="Draw today's weather and write one sentence."></textarea></label>
-            <label>Points possible <input id="ie-points" type="number" min="0" value="10"></label>
+          <div id="ie-field-assignment" class="ie-field rte-group">
+            <div class="rte-label">Instructions</div>
+            <div class="rte-toolbar">
+              <button type="button" class="rte-btn" data-cmd="bold" title="Bold"><b>B</b></button>
+              <button type="button" class="rte-btn" data-cmd="italic" title="Italic"><i>I</i></button>
+              <button type="button" class="rte-btn" data-cmd="underline" title="Underline"><u>U</u></button>
+              <span class="rte-sep"></span>
+              <button type="button" class="rte-btn" data-cmd="formatBlock" data-val="h2" title="Heading">H2</button>
+              <button type="button" class="rte-btn" data-cmd="formatBlock" data-val="h3" title="Sub-heading">H3</button>
+              <button type="button" class="rte-btn" data-cmd="formatBlock" data-val="p" title="Paragraph">¶</button>
+              <span class="rte-sep"></span>
+              <button type="button" class="rte-btn" data-cmd="insertUnorderedList" title="Bullet list">• List</button>
+              <button type="button" class="rte-btn" data-cmd="insertOrderedList" title="Numbered list">1. List</button>
+              <span class="rte-sep"></span>
+              <button type="button" class="rte-btn rte-link-btn" title="Add link">🔗 Link</button>
+              <button type="button" class="rte-btn rte-youtube-btn" title="Embed YouTube">▶ YouTube</button>
+            </div>
+            <div id="ie-body-assignment" class="rte-editor lesson-body" contenteditable="true"
+              data-placeholder="Draw today's weather and write one sentence."></div>
+            <label style="margin-top:.75rem">Points possible <input id="ie-points" type="number" min="0" value="10"></label>
           </div>
 
           <div id="ie-field-quiz" class="ie-field">

public/admin.js

@@ -395,7 +395,7 @@ async function openItemEditor(unitId, itemId) {
     $('#ie-type').value = item.type;
     $('#ie-title').value = item.title;
     $('#ie-body-lesson').innerHTML = item.body || '';
-    $('#ie-body-assignment').value = item.body;
+    $('#ie-body-assignment').innerHTML = item.body || '';
     $('#ie-points').value = item.points || 10;
     $('#ie-due-date').value = item.due_date || '';
     $('#ie-allow-retakes').checked = !!item.allow_retakes;
@@ -417,7 +417,7 @@ async function openItemEditor(unitId, itemId) {
     $('#ie-type').value = 'lesson';
     $('#ie-title').value = '';
     $('#ie-body-lesson').innerHTML = '';
-    $('#ie-body-assignment').value = '';
+    $('#ie-body-assignment').innerHTML = '';
     $('#ie-points').value = 10;
     $('#ie-due-date').value = '';
     $('#ie-allow-retakes').checked = false;
@@ -446,57 +446,60 @@ $('#ie-type').addEventListener('change', updateItemFieldVisibility);
 
 // ---------- rich text editor (lesson body) ----------
 
-function getLessonBody() {
-  const html = $('#ie-body-lesson').innerHTML.trim();
+function getRteBody(el) {
+  const html = el.innerHTML.trim();
   return html === '<br>' ? '' : html;
 }
+function getLessonBody() { return getRteBody($('#ie-body-lesson')); }
+function getAssignmentBody() { return getRteBody($('#ie-body-assignment')); }
 
-let rtesavedRange = null;
-
-// Save selection whenever the editor loses focus (e.g. when clicking a toolbar button)
-$('#ie-body-lesson').addEventListener('blur', () => {
-  const sel = window.getSelection();
-  rtesavedRange = sel.rangeCount > 0 ? sel.getRangeAt(0).cloneRange() : null;
-});
-
-function rteRestoreAndExec(cmd, val = null) {
-  $('#ie-body-lesson').focus();
-  if (rtesavedRange) {
-    const sel = window.getSelection();
-    sel.removeAllRanges();
-    sel.addRange(rtesavedRange);
-  }
-  document.execCommand(cmd, false, val);
-}
-
-// Format buttons (bold, italic, heading, lists, etc.)
+// Format buttons — mousedown+preventDefault keeps focus/selection in the editor
 document.querySelectorAll('.rte-btn[data-cmd]').forEach((btn) => {
-  btn.addEventListener('click', () => {
-    rteRestoreAndExec(btn.dataset.cmd, btn.dataset.val || null);
+  btn.addEventListener('mousedown', (e) => {
+    e.preventDefault();
+    const editor = btn.closest('.rte-group').querySelector('.rte-editor');
+    editor.focus();
+    document.execCommand(btn.dataset.cmd, false, btn.dataset.val || null);
   });
 });
 
-// Link button
-$('#rte-link-btn').addEventListener('click', () => {
-  const savedRange = rtesavedRange;
+// Link buttons
+document.querySelectorAll('.rte-link-btn').forEach((btn) => {
+  btn.addEventListener('mousedown', (e) => {
+    e.preventDefault();
+    const editor = btn.closest('.rte-group').querySelector('.rte-editor');
+    editor.focus();
+    const sel = window.getSelection();
+    const savedRange = sel.rangeCount > 0 ? sel.getRangeAt(0).cloneRange() : null;
     const url = prompt('Enter URL (e.g. https://example.com):');
     if (url) {
-    rteRestoreAndExec('createLink', url);
+      editor.focus();
+      if (savedRange) { sel.removeAllRanges(); sel.addRange(savedRange); }
+      document.execCommand('createLink', false, url);
     }
+  });
 });
 
-// YouTube embed button
-$('#rte-youtube-btn').addEventListener('click', () => {
+// YouTube embed buttons
+document.querySelectorAll('.rte-youtube-btn').forEach((btn) => {
+  btn.addEventListener('mousedown', (e) => {
+    e.preventDefault();
+    const editor = btn.closest('.rte-group').querySelector('.rte-editor');
+    editor.focus();
+    const sel = window.getSelection();
+    const savedRange = sel.rangeCount > 0 ? sel.getRangeAt(0).cloneRange() : null;
     const input = prompt('YouTube URL or video ID:');
     if (!input) return;
     const match = input.match(/(?:youtu\.be\/|youtube\.com\/(?:embed\/|watch\?v=))([a-zA-Z0-9_-]{11})/);
     const id = match ? match[1] : input.trim();
     if (id) {
-    rteRestoreAndExec(
-      'insertHTML',
+      editor.focus();
+      if (savedRange) { sel.removeAllRanges(); sel.addRange(savedRange); }
+      document.execCommand('insertHTML', false,
         `<br><iframe width="560" height="315" src="https://www.youtube.com/embed/${id}" frameborder="0" allowfullscreen style="max-width:100%;border-radius:10px"></iframe><br>`
       );
     }
+  });
 });
 
 // ---------- scan a page (photo -> lesson/quiz content via local Ollama) ----------
@@ -624,8 +627,7 @@ $('#import-go-btn').addEventListener('click', async () => {
       ? `<details><summary>📄 ${result.originalName}</summary><iframe src="${result.htmlUrl}" style="width:100%;border:1px solid #ccc;border-radius:4px;margin-top:.5em;display:block;" onload="try{this.style.height=this.contentDocument.documentElement.scrollHeight+32+'px'}catch(e){this.style.height='500px'}"></iframe><p><a href="${result.url}" download="${result.originalName}">⬇️ Download ${result.originalName}</a></p></details>`
       : `<a href="${result.url}" target="_blank">📄 ${result.originalName}</a>`;
     if (type === 'assignment') {
-      const cur = $('#ie-body-assignment').value;
-      $('#ie-body-assignment').value = cur ? cur + '\n\n' + embed : embed;
+      $('#ie-body-assignment').innerHTML += embed;
     } else {
       $('#ie-body-lesson').innerHTML += embed;
     }
@@ -691,7 +693,7 @@ $('#item-form').addEventListener('submit', async (e) => {
     unitId: Number($('#ie-unit-id').value),
     type,
     title,
-    body: type === 'lesson' ? getLessonBody() : type === 'assignment' ? $('#ie-body-assignment').value : '',
+    body: type === 'lesson' ? getLessonBody() : type === 'assignment' ? getAssignmentBody() : '',
     points: type === 'assignment' ? Number($('#ie-points').value) || 0 : 0,
     refId: type === 'spelling_practice' || type === 'spelling_test' ? Number($('#ie-list').value)
          : type === 'flashcards' ? Number($('#ie-deck').value) : null,