clan_cli: add select command

pkgs/clan-cli/clan_cli/select.py

@@ -0,0 +1,17 @@
+import argparse
+import json
+
+from clan_cli.flake import Flake
+
+
+def select_command(args: argparse.Namespace) -> None:
+    flake = Flake(args.flake.path)
+    print(json.dumps(flake.select(args.selector), indent=4))
+
+
+def register_parser(parser: argparse.ArgumentParser) -> None:
+    parser.set_defaults(func=select_command)
+    parser.add_argument(
+        "selector",
+        help="select from a flake",
+    )