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/library.go

@@ -0,0 +1,26 @@
+package content
+
+import (
+	_ "embed"
+)
+
+// Embedded library assets
+//
+//go:embed assets/insertr.min.js
+var libraryMinJS string
+
+//go:embed assets/insertr.js
+var libraryJS string
+
+// GetLibraryScript returns the appropriate library version
+func GetLibraryScript(minified bool) string {
+	if minified {
+		return libraryMinJS
+	}
+	return libraryJS
+}
+
+// GetLibraryVersion returns the current embedded library version
+func GetLibraryVersion() string {
+	return "1.0.0"
+}