Follow-up to e2548f69: add missing paths module, fix gallery extension

modules/paths.py

@@ -0,0 +1,28 @@
+import sys
+from pathlib import Path
+
+
+def resolve_user_data_dir():
+    """
+    Resolve the user_data directory path. Order of precedence:
+    1. --user-data-dir CLI flag (pre-parsed from sys.argv before argparse)
+    2. Auto-detect: if ./user_data doesn't exist but ../user_data does, use ../user_data
+    3. Default: 'user_data'
+    """
+    script_dir = Path(__file__).resolve().parent.parent
+
+    # Check sys.argv for --user-data-dir before argparse runs
+    for i, arg in enumerate(sys.argv):
+        if arg == '--user-data-dir' and i + 1 < len(sys.argv):
+            return Path(sys.argv[i + 1])
+        elif arg.startswith('--user-data-dir='):
+            return Path(arg.split('=', 1)[1])
+
+    # Auto-detect: check if user_data exists locally vs one folder up
+    local_path = script_dir / 'user_data'
+    parent_path = script_dir.parent / 'user_data'
+
+    if not local_path.exists() and parent_path.exists():
+        return parent_path
+
+    return Path('user_data')