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/internal/models/content.go

@@ -0,0 +1,34 @@
+package models
+
+import (
+	"time"
+)
+
+// ContentItem represents a piece of content in the database
+// This matches the structure used by the CLI client and JavaScript client
+type ContentItem struct {
+	ID        string    `json:"id" db:"id"`
+	SiteID    string    `json:"site_id" db:"site_id"`
+	Value     string    `json:"value" db:"value"`
+	Type      string    `json:"type" db:"type"`
+	CreatedAt time.Time `json:"created_at" db:"created_at"`
+	UpdatedAt time.Time `json:"updated_at" db:"updated_at"`
+}
+
+// ContentResponse represents the API response structure for multiple items
+type ContentResponse struct {
+	Content []ContentItem `json:"content"`
+	Error   string        `json:"error,omitempty"`
+}
+
+// CreateContentRequest represents the request structure for creating content
+type CreateContentRequest struct {
+	ID    string `json:"id" validate:"required"`
+	Value string `json:"value" validate:"required"`
+	Type  string `json:"type" validate:"required,oneof=text markdown link"`
+}
+
+// UpdateContentRequest represents the request structure for updating content
+type UpdateContentRequest struct {
+	Value string `json:"value" validate:"required"`
+}