feat: complete full-stack development integration

🎯 Major Achievement: Insertr is now a complete, production-ready CMS

## 🚀 Full-Stack Integration Complete
- ✅ HTTP API Server: Complete REST API with SQLite database
- ✅ Smart Client Integration: Environment-aware API client
- ✅ Unified Development Workflow: Single command full-stack development
- ✅ Professional Tooling: Enhanced build, status, and health checking

## 🔧 Development Experience
- Primary: `just dev` - Full-stack development (demo + API server)
- Alternative: `just demo-only` - Demo site only (special cases)
- Build: `just build` - Complete stack (library + CLI + server)
- Status: `just status` - Comprehensive project overview

## 📦 What's Included
- **insertr-server/**: Complete HTTP API server with SQLite database
- **Smart API Client**: Environment detection, helpful error messages
- **Enhanced Build Pipeline**: Builds library + CLI + server in one command
- **Integrated Tooling**: Status checking, health monitoring, clean workflows

## 🧹 Cleanup
- Removed legacy insertr-old code (no longer needed)
- Simplified workflow (full-stack by default)
- Updated all documentation to reflect complete CMS

## 🎉 Result
Insertr is now a complete, professional CMS with:
- Real content persistence via database
- Professional editing interface
- Build-time content injection
- Zero-configuration deployment
- Production-ready architecture

Ready for real-world use! 🚀

insertr-server/go.sum

@@ -0,0 +1,4 @@
+github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY=
+github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ=
+github.com/mattn/go-sqlite3 v1.14.32 h1:JD12Ag3oLy1zQA+BNn74xRgaBbdhbNIDYvQUEuuErjs=
+github.com/mattn/go-sqlite3 v1.14.32/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=