Add seed script with 7 trees, markdown rendering, and dark mode docs

- Add comprehensive seed script with 7 troubleshooting decision trees
  - Tier 1: Password Reset, Outlook/Email, VPN, Printer Problems
  - Tier 2: Slow Computer, Network Connectivity
  - Tier 3: File Share Access Problems
- Add markdown rendering with react-markdown package
  - MarkdownContent component for session player and node editor
  - Preview toggle in description fields
- Update documentation to reflect dark mode is complete
- Update all progress tracking docs with recent changes

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

CLAUDE-SETUP.md

@@ -2,7 +2,7 @@
 
 This document catalogs all tools, plugins, and MCP servers available to Claude Code when developing Apoklisis, along with guidelines for their effective use.
 
-**Last Updated**: 2026-01-28
+**Last Updated**: 2026-01-29
 **Project**: Apoklisis
 **Working Directory**: `c:\Dev\Projects\Apoklisis`
 **Platform**: Windows (win32)
@@ -432,13 +432,15 @@ curl -X GET "http://localhost:8000/api/v1/trees" -H "Authorization: Bearer <toke
 - ✅ NodePicker with type-grouped dropdown
 - ✅ SharedLinksMap for detecting nodes with multiple sources
 - ✅ Modal with scrollable content, fixed header/footer
+- ✅ Markdown rendering in session player and node editor
+- ✅ Dark mode / theme toggle
 - ⏳ Validation polish (required fields, orphan detection)
 
 **Phase 2 Remaining** - ⏳ **Planned**
 
 - Team management features
 - Mobile responsive improvements
-- User preferences (dark mode)
+- ~~User preferences (dark mode)~~ ✅ **COMPLETE**
 
 ### Backend File Structure