Add video chapter/timeline navigation feature

Implement timeline chapters for webinar and bootcamp videos with click-to-jump functionality:

**Components:**
- VideoPlayerWithChapters: Plyr.io-based player with chapter support
- TimelineChapters: Clickable chapter markers with active state
- ChaptersEditor: Admin UI for managing video chapters

**Features:**
- YouTube videos: Clickable timestamps that jump to specific time
- Embed videos: Static timeline display (non-clickable)
- Real-time chapter tracking during playback
- Admin-defined accent color for Plyr theme
- Auto-hides timeline when no chapters configured

**Database:**
- Add chapters JSONB column to products table (webinars)
- Add chapters JSONB column to bootcamp_lessons table
- Create indexes for faster queries

**Updated Pages:**
- WebinarRecording: Two-column layout (video + timeline)
- Bootcamp: Per-lesson chapter support
- AdminProducts: Chapter editor for webinars
- CurriculumEditor: Chapter editor for lessons

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

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

supabase/migrations/20251231000000_add_video_chapters.sql

@@ -0,0 +1,17 @@
+-- Add chapters support to products table (for webinars)
+ALTER TABLE products
+  ADD COLUMN IF NOT EXISTS chapters JSONB DEFAULT '[]';
+
+-- Add chapters support to bootcamp_lessons table
+ALTER TABLE bootcamp_lessons
+  ADD COLUMN IF NOT EXISTS chapters JSONB DEFAULT '[]';
+
+-- Add comments for documentation
+COMMENT ON COLUMN products.chapters IS 'Video chapters/timeline markers stored as JSON array of {time: number, title: string}';
+COMMENT ON COLUMN bootcamp_lessons.chapters IS 'Video chapters/timeline markers stored as JSON array of {time: number, title: string}';
+
+-- Create index for faster queries on products with chapters
+CREATE INDEX IF NOT EXISTS idx_products_has_chapters ON products ((jsonb_array_length(chapters) > 0));
+
+-- Create index for faster queries on lessons with chapters
+CREATE INDEX IF NOT EXISTS idx_bootcamp_lessons_has_chapters ON bootcamp_lessons ((jsonb_array_length(chapters) > 0));