Add time_range filter to Research Bridge API and optimize SearXNG config for news

src/search/searxng.py

@@ -59,11 +59,12 @@ class SearXNGClient:
         query_string = "&".join(query_parts)
         return f"{self.base_url}/search?{query_string}"
 
-    async def search(self, request: SearchRequest) -> SearchResponse:
+    async def search(self, request: SearchRequest, time_range: str | None = None) -> SearchResponse:
         """Execute search query against SearXNG.
 
         Args:
             request: SearchRequest with query, engines, page
+            time_range: Optional time filter (day, week, month, year)
 
         Returns:
             SearchResponse with results
@@ -77,6 +78,10 @@ class SearXNGClient:
             "engines": ",".join(request.engines),
             "pageno": request.page,
         }
+        
+        # Add time_range if specified (SearXNG supports: day, week, month, year)
+        if time_range:
+            params["time_range"] = time_range
 
         url = self._build_url(params)
         client = self._get_client()