fix: print config hint when logs token is missing

--once --logs now exits 2 with a clear pointer to SHUSUB2_LOGS_TOKEN /
~/.config/shusub2/logs-token instead of a raw HTTP 401 traceback; the TUI
logs page reuses the same hint.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_payload.py

@@ -469,6 +469,26 @@ class Sub2APILogsTests(unittest.TestCase):
                 else:
                     os.environ["SHUSUB2_LOGS_TOKEN_FILE"] = old_value
 
+    def test_once_logs_without_token_prints_hint_and_exits_2(self) -> None:
+        mod = load_module()
+        old_token = os.environ.pop("SHUSUB2_LOGS_TOKEN", None)
+        old_file = os.environ.get("SHUSUB2_LOGS_TOKEN_FILE")
+        os.environ["SHUSUB2_LOGS_TOKEN_FILE"] = "/nonexistent/shusub2/logs-token"
+        err = io.StringIO()
+        try:
+            with contextlib.redirect_stderr(err):
+                rc = mod.main(["--once", "--logs", "--no-version-check"])
+        finally:
+            if old_token is not None:
+                os.environ["SHUSUB2_LOGS_TOKEN"] = old_token
+            if old_file is None:
+                os.environ.pop("SHUSUB2_LOGS_TOKEN_FILE", None)
+            else:
+                os.environ["SHUSUB2_LOGS_TOKEN_FILE"] = old_file
+
+        self.assertEqual(rc, 2)
+        self.assertIn("logs token not configured", err.getvalue())
+
     def test_default_logs_url_defaults_to_sub2apicn(self) -> None:
         mod = load_module()
         old_url = os.environ.pop("SHUSUB2_LOGS_URL", None)