Add lessons module, rate cycles, EC2 deploy scripts, and help content

- Lessons module: lesson types, instructors, schedule slots, enrollments,
  sessions (list + week grid view), lesson plans, grading scales, templates
- Rate cycles: replace monthly_rate with billing_interval + billing_unit on
  enrollments; add weekly/monthly/quarterly rate presets to lesson types and
  schedule slots with auto-fill on enrollment form
- Member detail page: tabbed layout for details, identity documents, enrollments
- Sessions week view: custom 7-column grid replacing react-big-calendar
- Music store seed: instructors, lesson types, slots, enrollments, sessions,
  grading scale, lesson plan template
- Scrollbar styling: themed to match sidebar/app palette
- deploy/: EC2 setup and redeploy scripts, nginx config, systemd service
- Help: add Lessons category (overview, types, instructors, slots, enrollments,
  sessions, plans/grading); collapsible sidebar with independent scroll;
  remove POS/accounting references from docs

deploy/nginx.conf

@@ -0,0 +1,47 @@
+server {
+    listen 80;
+    server_name YOUR_DOMAIN www.YOUR_DOMAIN;
+    # Certbot will automatically add HTTPS redirect and SSL config below this line
+
+    root /opt/lunarfront/packages/admin/dist;
+    index index.html;
+
+    # Proxy API requests to Bun backend
+    location /v1/ {
+        proxy_pass http://localhost:8000;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_read_timeout 60s;
+        client_max_body_size 20M;
+    }
+
+    # WebDAV passthrough (all HTTP methods)
+    location /webdav/ {
+        proxy_pass http://localhost:8000;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_read_timeout 120s;
+        client_max_body_size 100M;
+    }
+
+    # SPA fallback — serve index.html for all unmatched paths
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    # Cache hashed static assets aggressively
+    location /assets/ {
+        expires 1y;
+        add_header Cache-Control "public, immutable";
+    }
+
+    gzip on;
+    gzip_vary on;
+    gzip_types text/plain text/css application/json application/javascript text/xml application/xml image/svg+xml;
+}