fix: reset ssrf whitelist on config reload and document config refresh

tests/config/test_config_migration.py

@@ -1,6 +1,18 @@
 import json
+import socket
+from unittest.mock import patch
 
 from nanobot.config.loader import load_config, save_config
+from nanobot.security.network import validate_url_target
+
+
+def _fake_resolve(host: str, results: list[str]):
+    """Return a getaddrinfo mock that maps the given host to fake IP results."""
+    def _resolver(hostname, port, family=0, type_=0):
+        if hostname == host:
+            return [(socket.AF_INET, socket.SOCK_STREAM, 0, "", (ip, 0)) for ip in results]
+        raise socket.gaierror(f"cannot resolve {hostname}")
+    return _resolver
 
 
 def test_load_config_keeps_max_tokens_and_ignores_legacy_memory_window(tmp_path) -> None:
@@ -126,3 +138,23 @@ def test_onboard_refresh_backfills_missing_channel_fields(tmp_path, monkeypatch)
     assert result.exit_code == 0
     saved = json.loads(config_path.read_text(encoding="utf-8"))
     assert saved["channels"]["qq"]["msgFormat"] == "plain"
+
+
+def test_load_config_resets_ssrf_whitelist_when_next_config_is_empty(tmp_path) -> None:
+    whitelisted = tmp_path / "whitelisted.json"
+    whitelisted.write_text(
+        json.dumps({"tools": {"ssrfWhitelist": ["100.64.0.0/10"]}}),
+        encoding="utf-8",
+    )
+    defaulted = tmp_path / "defaulted.json"
+    defaulted.write_text(json.dumps({}), encoding="utf-8")
+
+    load_config(whitelisted)
+    with patch("nanobot.security.network.socket.getaddrinfo", _fake_resolve("ts.local", ["100.100.1.1"])):
+        ok, err = validate_url_target("http://ts.local/api")
+        assert ok, err
+
+    load_config(defaulted)
+    with patch("nanobot.security.network.socket.getaddrinfo", _fake_resolve("ts.local", ["100.100.1.1"])):
+        ok, _ = validate_url_target("http://ts.local/api")
+        assert not ok