fix: --reset no longer requires local Slack export path

test_reset_only_writes failed in CI (no ~/Downloads export) while
passing on a laptop that has the Levkin export. Skip SlackExport load
when --reset returns early.

scripts/auto-cherry-pick.py

@@ -355,10 +355,6 @@ def main() -> int:
         if not arg.startswith("-") and Path(arg).expanduser().is_dir():
             export_path = Path(arg).expanduser().resolve()
 
-    sys.path.insert(0, str(REPO_ROOT))
-    from slack_export import SlackExport
-
-    export = SlackExport(export_path)
     manifest: dict = {"channels": {}, "users": {}}
     if MANIFEST_PATH.is_file():
         manifest = json.loads(MANIFEST_PATH.read_text(encoding="utf-8"))
@@ -377,6 +373,10 @@ def main() -> int:
             )
         return 0
 
+    sys.path.insert(0, str(REPO_ROOT))
+    from slack_export import SlackExport
+
+    export = SlackExport(export_path)
     channels = manifest.setdefault("channels", {})
     stats: dict[str, int] = {}