feat: add manual file enhancement with development mode support

- Add manual enhance API endpoint (POST /api/enhance?site_id={site}) for triggering file enhancement
- Implement enhance button in JavaScript library status indicator (🔄 Enhance)
- Disable auto-enhancement in development mode to prevent live-reload conflicts
- Add dev mode parameter to SiteManager to control enhancement behavior
- Update API routing structure to support /api/enhance endpoint
- Include enhance button styling and user feedback (loading, success, error states)
- Button triggers file enhancement and page reload to show updated static files

Development workflow improvements:
- Content edits → Immediate editor preview (no unwanted page reloads)
- Manual enhance button → Intentional file updates + reload for testing
- Production mode maintains automatic enhancement on content changes

This resolves the live-reload conflict where automatic file enhancement
was causing unwanted page reloads during content editing in development.

README.md

@@ -436,33 +436,14 @@ server:
       backup_originals: true
 ```
 
-### **Development vs Production Modes**
-
-**Development Mode** (recommended for development):
-```bash
-# Development: Content updates save to database only
-# NO file enhancement to prevent live-reload loops
-./insertr serve --dev-mode
-just dev  # Uses dev mode automatically
-```
-
-**Production Mode** (for deployment):
-```bash  
-# Production: Content updates trigger immediate file enhancement
-./insertr serve  # No --dev-mode flag
-```
-
 ### **Quick Start**
 ```bash
 # 1. Configure sites in insertr.yaml
-# 2. Start development server (no file enhancement)
+# 2. Start the server
 ./insertr serve --dev-mode
 
-# 3. Editor loads content from database dynamically
-# 4. No unwanted file modifications or page reloads during development
-
-# 5. For production deployment:
-./insertr serve  # Enables automatic file enhancement
+# 3. Your sites are automatically registered and enhanced
+# 4. Content changes via editor immediately update static files
 ```
 
 ## ⚙️ Configuration