Add product-level video source toggle and improve curriculum UX

- Add video source toggle UI (YouTube/Embed) to product edit form for bootcamps
- Remove Bootcamp menu from admin navigation (curriculum managed via Products page)
- Remove tabs from product add/edit modal (simplified to single form)
- Improve ProductCurriculum layout from 3-column (3|5|4) to 2-column (4|8)
- Modules and lessons now in left sidebar with accordion-style expansion
- Lesson editor takes 67% width instead of 33% for better content editing UX
- Add helpful tip about configuring both video sources for redundancy

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/components/AppLayout.tsx

@@ -43,7 +43,6 @@ const userNavItems: NavItem[] = [
 const adminNavItems: NavItem[] = [
   { label: 'Dashboard', href: '/admin', icon: LayoutDashboard },
   { label: 'Produk', href: '/admin/products', icon: Package },
-  { label: 'Bootcamp', href: '/admin/bootcamp', icon: BookOpen },
   { label: 'Konsultasi', href: '/admin/consulting', icon: Video },
   { label: 'Order', href: '/admin/orders', icon: Receipt },
   { label: 'Member', href: '/admin/members', icon: Users },