LearnSpace: full-stack educational whiteboard platform

Node.js/Express backend + vanilla JS frontend.
Features: real-time collaborative whiteboard (SSE), multi-page support,
LaTeX formulas, shapes/connectors, coordinate systems, number lines,
compass, zoom/pan, Catmull-Rom pencil smoothing, ruler/protractor with
rotation & resize controls, minimap navigation overlay, auto-measurements,
multi-page thumbnails sidebar, PNG export, page templates.
Student/teacher workflows: classes, assignments, library, dashboard.
Mobile responsive. SQLite (better-sqlite3).

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

backend/src/routes/lessons.js

@@ -0,0 +1,21 @@
+const express = require('express');
+const router  = express.Router();
+const { authMiddleware, requireRole } = require('../middleware/auth');
+const c = require('../controllers/lessonController');
+
+router.use(authMiddleware);
+
+router.get('/:id',              c.get);
+router.post('/:id/complete',    c.markComplete);
+router.put('/:id/note',         c.saveNote);
+router.get('/:id/comments',     c.listComments);
+router.post('/:id/comments',    c.addComment);
+router.delete('/:id/comments/:cid', c.deleteComment);
+
+// Teacher/admin only
+router.post('/',             requireRole('teacher','admin'), c.create);
+router.put('/:id',           requireRole('teacher','admin'), c.update);
+router.delete('/:id',        requireRole('teacher','admin'), c.remove);
+router.put('/:id/blocks',    requireRole('teacher','admin'), c.saveBlocks);
+
+module.exports = router;