Add kid engagement features and planner drag-and-drop

- Streak tracker: server-side streak counting per kid, celebration overlay
  when all today's tasks are done for the first time that day
- Kid themes: 5 colour palettes (blue/green/purple/orange/pink), picked via
  colour dots on the kid home screen; parents can set it from the Kids panel
- Grading badge: Grading nav pill turns red and shows a pending count
- Print worksheets: 🖨 Worksheet button per word list in admin Spelling panel;
  kids also get "Print my words" on the Spelling tab
- Parent feedback: gold 💬 badge on Today rows with unread comments; more
  prominent callout styling inside the assignment view
- Planner drag-and-drop: tasks can be dragged between days; PATCH
  /api/schedule/:id moves the task, drop zones highlight on hover

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

public/admin.html

@@ -45,6 +45,7 @@
           <select id="new-student-emoji" aria-label="Avatar">
             <option>🦊</option><option>🐸</option><option>🦄</option><option>🐯</option>
             <option>🐼</option><option>🦖</option><option>🐙</option><option>🦉</option>
+            <option>🐻</option><option>🐰</option><option>🦁</option><option>🐶</option>
           </select>
           <button type="submit">Add kid</button>
         </form>
@@ -149,6 +150,17 @@
             <p id="scan-status" class="hint"></p>
           </div>
 
+          <!-- Import from Homeschool folder: visible for lesson, assignment, quiz types -->
+          <div id="ie-import-section" class="scan-card" hidden>
+            <strong>📂 Import from Homeschool folder</strong>
+            <div class="scan-controls">
+              <select id="import-file-select" style="flex:1"><option value="">— choose a file —</option></select>
+              <button type="button" id="import-load-btn" class="secondary">↓ Load files</button>
+              <button type="button" id="import-go-btn" class="secondary" disabled>📥 Import</button>
+            </div>
+            <p id="import-status" class="hint"></p>
+          </div>
+
           <div id="ie-field-lesson" class="ie-field">
             <label>Lesson content (text, or paste HTML — images/YouTube embeds allowed)
               <textarea id="ie-body-lesson" rows="8" placeholder="Weather is what the sky and air are doing right now.&#10;&#10;&lt;iframe src=&quot;https://www.youtube.com/embed/VIDEO_ID&quot;&gt;&lt;/iframe&gt;"></textarea>
@@ -258,7 +270,7 @@
             <input type="hidden" id="list-id">
             <input id="list-name" placeholder="List name (e.g. Week of July 6)" aria-label="List name">
             <textarea id="list-words" rows="8"
-              placeholder="One word per line. Optionally add sentence and definition with | like:&#10;receive | Did you receive my letter? | to get or accept something"></textarea>
+              placeholder="One word per line. Paste any list from your curriculum!&#10;&#10;Add an example sentence with |&#10;receive | Did you receive my letter?&#10;&#10;Or just a plain list:&#10;because&#10;enough&#10;friend"></textarea>
             <div class="row-actions">
               <button type="submit">Save list</button>
               <button type="button" id="list-cancel" class="secondary">Clear</button>