ui: update max turns defaults and timeout copy

app.py

@@ -2377,7 +2377,8 @@ def build_research_agent(
     if final_answer is None:
         final_answer = (
             "I could not finish a complete research answer within the configured turns. "
-            "Try increasing max turns."
+            "To keep the hosted demo cost manageable, this Space limits max turns to 50. "
+            "For longer runs, try QUEST offline with your own APIs and a higher turn limit."
         )
     else:
         final_answer = ensure_markdown_table_blank_lines(final_answer)
@@ -2577,7 +2578,7 @@ with gr.Blocks(
                     label="Max Turns",
                     minimum=2,
                     maximum=50,
-                    value=15,
+                    value=25,
                     step=1,
                     elem_id="quest-max-turns",
                 )