fix: Decode HTML entities in chat responses and improve n8n error handling

- Add HTML entity decoding for chat responses (fixes ' display issue)
- Add timeout handling for n8n webhook requests (30s chat, 10s status)
- Improve error logging with detailed error information
- Add N8N_SECRET_TOKEN support for authentication
- Better fallback handling when n8n is unavailable
- Fix server-side HTML entity decoding for chat and status endpoints

lib/html-decode.ts

@@ -0,0 +1,41 @@
+/**
+ * Decode HTML entities in strings
+ * Converts ' " & < > etc. to their actual characters
+ */
+export function decodeHtmlEntities(text: string): string {
+  if (!text || typeof text !== 'string') {
+    return text;
+  }
+
+  // Create a temporary element to decode HTML entities
+  const textarea = document.createElement('textarea');
+  textarea.innerHTML = text;
+  return textarea.value;
+}
+
+/**
+ * Server-side HTML entity decoding (for Node.js/Next.js API routes)
+ */
+export function decodeHtmlEntitiesServer(text: string): string {
+  if (!text || typeof text !== 'string') {
+    return text;
+  }
+
+  // Map of common HTML entities
+  const entityMap: Record<string, string> = {
+    '&apos;': "'",
+    '&quot;': '"',
+    '&amp;': '&',
+    '&lt;': '<',
+    '&gt;': '>',
+    '&#39;': "'",
+    '&#x27;': "'",
+    '&#x2F;': '/',
+    '&#x60;': '`',
+    '&#x3D;': '=',
+  };
+
+  return text.replace(/&[#\w]+;/g, (entity) => {
+    return entityMap[entity] || entity;
+  });
+}