fix: disable auto-enhancement in development mode to prevent live-reload loops

- Add dev_mode parameter to SiteManager constructor
- Modify IsAutoEnhanceEnabled() to return false when dev_mode is true
- Update serve.go to pass dev_mode flag to SiteManager
- Add ForceEnhanceEnabled() method for testing production behavior in development
- Update documentation to explain development vs production mode behavior

This fixes the development workflow where content updates would trigger
file modifications that caused unwanted page reloads in live-server.

Development mode: Content saved to database only, editor loads dynamically
Production mode: Content saved + files enhanced for immediate static deployment

COMMANDS.md

@@ -104,9 +104,23 @@ When running `insertr serve`, the server automatically:
 - **Auto-updates files** when content changes via API
 - **Creates backups** of original files (if enabled)
 
-**Live Enhancement Process:**
+**Development vs Production Behavior:**
+
+**Development Mode** (`--dev-mode`):
+- ✅ Content changes saved to database
+- ❌ File enhancement **disabled** (prevents live-reload loops)
+- ✅ Editor loads content dynamically from API
+- ✅ Perfect for `just dev` workflow
+
+**Production Mode** (no `--dev-mode`):
+- ✅ Content changes saved to database  
+- ✅ File enhancement **enabled**
+- ✅ Static files updated immediately
+- ✅ Changes live instantly
+
+**Live Enhancement Process (Production):**
 1. Content updated via API → Database updated
-2. If site has `auto_enhance: true` → File enhancement triggered
+2. If site has `auto_enhance: true` AND not in dev mode → File enhancement triggered
 3. Static files updated in-place → Changes immediately live
 
 ### API Endpoints