fix: resolve console errors (localStorage in Worker, favicon, Tailwind CDN)

Issues fixed:
1. Web Worker localStorage error - Remove localStorage calls from worker
   - Worker cannot access localStorage (browser context only)
   - Worker now sends data to main thread via postMessage
   - Main thread handles all localStorage operations

2. Add favicon to avoid 404 error
   - Use inline SVG favicon (llama emoji)
   - No external file request

3. Optimize Tailwind CSS for production
   - Add tailwind.config.js for content scanning
   - Add app/web/static/css/input.css (Tailwind directives)
   - Update package.json with tailwind build commands
   - Update Dockerfile multi-stage build:
     * Stage 1: Node.js - compile Tailwind CSS
     * Stage 2: Python - install dependencies
     * Stage 3: Runtime - use compiled CSS
   - Update index.html to use compiled output.css
   - Add fallback to CDN for development

4. Add DEVELOPMENT.md documentation
   - Setup instructions for local development
   - Tailwind CSS workflow (watch mode)
   - Docker build explanation
   - Development tips and best practices

Benefits:
- No more localStorage errors in console
- No more 404 favicon requests
- Optimized CSS for production (~30KB minified)
- Clear development workflow
- Multi-stage Docker build is efficient (~300MB image)

app/web/static/js/data-sync.worker.js

@@ -59,16 +59,8 @@ async function syncData() {
     const health = await fetchHealth();
     const modelsData = await fetchModels();
     
-    // Salvare in localStorage
-    if (health) {
-        localStorage.setItem("llm_monitor_health", JSON.stringify(health));
-    }
-    
-    if (modelsData) {
-        localStorage.setItem("llm_monitor_models", JSON.stringify(modelsData));
-    }
-    
     // Notificare il main thread
+    // (il main thread gestisce localStorage)
     self.postMessage({
         type: "DATA_UPDATED",
         health,