Switch feedback reverse proxy from IIS to NGINX

- Add nginx-wp-suite.conf: static site + /api/feedback proxy to the Power
  Automate trigger (SNI on, Host header, POST-only, body cap)
- Remove IIS web.config
- Update feedback-config.js comment and DEPLOYMENT.md to the NGINX setup

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

index.html

@@ -4,6 +4,7 @@
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <title>Work Package Suite — Prime Controls</title>
+  <link rel="icon" href="favicon.ico" sizes="any">
   <link rel="stylesheet" href="theme-light.css">
   <style>
     * { margin: 0; padding: 0; box-sizing: border-box; }