Add NordVPN proxy rotation for geo-distributed web fetching

3 proxies: Tokyo (.154:3128), London (.71:3128), Sydney (.189:3128)
Random rotation per crawl — bypasses geo-blocks and rate limits

backend.py

@@ -159,11 +159,24 @@ def semantic_search(q: str = Query(...), limit: int = 10):
 
 import re
 import html as html_mod
+import random
+
+# NordVPN HTTP proxies for geo-distributed fetching
+PROXIES = [
+    "http://10.30.20.154:3128",  # Tokyo, Japan
+    "http://10.30.20.71:3128",   # London, UK
+    "http://10.30.20.189:3128",  # Sydney, Australia
+]
 
 def _fetch_and_index(url: str, category: str = ""):
     """Fetch a URL, extract text, and index into OpenSearch immediately."""
+    proxy_url = random.choice(PROXIES)
     try:
-        r = client.get(url, headers={"User-Agent": "Mozilla/5.0 (compatible; ResearchBot/1.0)"}, timeout=15.0)
+        # Create a per-request client with proxy
+        proxy_client = httpx.Client(proxy=proxy_url, timeout=15.0)
+        r = proxy_client.get(url,
+            headers={"User-Agent": "Mozilla/5.0 (compatible; ResearchBot/1.0)"},
+        )
         if r.status_code != 200:
             return None
         html_text = r.text