feat: Major documentation reorganization and unified Box design updates

## Documentation & Organization
- Moved copilot_issues.txt → 00_MASTER_ROADMAP.md (phases folder)
- Created Phase 9.79b.1 & 9.79b.2 plans for unified Box implementation
- Updated unified-box-design-deep-analysis.md with ChatGPT5 insights
- Added P2P documentation and examples (ping-pong, self-ping)

## Code Updates
- P2PBox: Reverted to original error state for demonstration
- VM: Enhanced BoxCall dispatch for unified approach
- Updated box factory, interpreter calls, and transport layer

## Cleanup & Privacy
- Removed private/ and private_test/ from git tracking
- Added private folders to .gitignore for security
- Cleaned root directory: moved backups, removed temp files
- Moved consultation files to docs/archive/consultations/

## Other Improvements
- Added object literal syntax improvement idea
- Updated CLAUDE.md with master roadmap reference
- Updated CURRENT_TASK.md with latest progress

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

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

.gitignore

@@ -45,6 +45,8 @@ nyash-rust/
 
 # 開発用秘密フォルダ（完全除外）
 /development/
+/private/
+/private_test/
 
 # Test files
 *.tmp
@@ -118,4 +120,7 @@ local_tests/
 
 # Font files (already in assets/)
 *.ttf
-*.otf
+*.otf
+
+# Backup files
+/backups/