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

README.md

@@ -178,18 +178,24 @@ Static Site Build → Insertr CLI Enhancement → Enhanced Deployment
 
 ## 🔧 Development Workflow
 
-### **Live Development**
+### **Live Development with Hot Reload**
 ```bash
 cd insertr-cli
 
-# Air watches Go files and rebuilds CLI
-# Post-build: starts development server
+# 🔥 Hot Reload: watches BOTH library AND CLI
 air
 
-# Edit parser code → Auto rebuild → Server restart
+# Library changes: lib/src/**/*.js → Auto rebuild library + CLI
+# CLI changes: cmd/**/*.go → Auto rebuild CLI  
+# Both trigger server restart with latest embedded assets
 # Visit localhost:3000 → Refresh to see changes
 ```
 
+**What Gets Hot Reloaded:**
+- JavaScript library changes (`lib/src/`)
+- Go CLI changes (`insertr-cli/`)  
+- Enhanced HTML output (real-time content injection)
+
 ### **Content ID Management**
 **Development Phase:**
 - Generated IDs are disposable and change freely