feat: complete code cleanup and create feature parity plan

Major Architecture Improvements:
- Separate JavaScript library (lib/) with proper build system
- Go CLI with embedded library using go:embed
- Hot reload development with Air integration
- Library + CLI build pipeline with npm run build

Code Cleanup:
- Remove obsolete assets (insertr-cli/assets/editor/)
- Clean up package.json metadata and dependencies
- Update .gitignore for new architecture
- Remove unused 'marked' dependency

New Documentation:
- Add comprehensive TODO.md with feature gap analysis
- Document critical gaps between prototype and current library
- Create phased implementation plan for feature parity
- Update DEVELOPMENT.md with hot reload workflow
- Add LIBRARY.md documenting new architecture

Hot Reload System:
- Air watches both Go CLI and JavaScript library
- Library changes trigger: rebuild → copy → CLI rebuild → serve
- Seamless development experience across full stack

Next Steps:
- Current library is basic proof-of-concept (prompt() editing)
- Archived prototype has production-ready features
- Phase 1 focuses on professional forms and authentication
- Phase 2 adds validation and content persistence

insertr-cli/pkg/content/enhancer.go

@@ -69,7 +69,8 @@ func (e *Enhancer) EnhanceFile(inputPath, outputPath string) error {
 	}
 
 	// Inject editor assets for development
-	e.injector.InjectEditorAssets(doc, true)
+	libraryScript := GetLibraryScript(true) // Use minified for better performance
+	e.injector.InjectEditorAssets(doc, true, libraryScript)
 
 	// Write enhanced HTML
 	if err := e.writeHTML(doc, outputPath); err != nil {