fix(cli): silence tirith prefetch install warnings at startup (#1452)

cli.py

@@ -4797,7 +4797,7 @@ class HermesCLI:
         # Ensure tirith security scanner is available (downloads if needed)
         try:
             from tools.tirith_security import ensure_installed
-            ensure_installed()
+            ensure_installed(log_failures=False)
         except Exception:
             pass  # Non-fatal — fail-open at scan time if unavailable