cli: also register common flags in subcommands

When a user runs --help on a subcommand they don't see some options such
as --options or --flake. To fix this we now register all common flags
also in subcommands.

pkgs/clan-cli/clan_cli/__init__.py

@@ -51,19 +51,14 @@ class AppendOptionAction(argparse.Action):
         lst.append(values[1])
 
 
-def create_parser(prog: str | None = None) -> argparse.ArgumentParser:
-    parser = argparse.ArgumentParser(
-        prog=prog,
-        description="The clan cli tool.",
-        epilog=(
-            """
-Online reference for the clan cli tool: https://docs.clan.lol/reference/cli/
-For more detailed information, visit: https://docs.clan.lol
-        """
-        ),
-        formatter_class=argparse.RawTextHelpFormatter,
-    )
+def flake_path(arg: str) -> str | Path:
+    flake_dir = Path(arg).resolve()
+    if flake_dir.exists() and flake_dir.is_dir():
+        return flake_dir
+    return arg
 
+
+def add_common_flags(parser: argparse.ArgumentParser) -> None:
     parser.add_argument(
         "--debug",
         help="Enable debug logging",
@@ -94,6 +89,32 @@ For more detailed information, visit: https://docs.clan.lol
         type=flake_path,
     )
 
+
+def register_common_flags(parser: argparse.ArgumentParser) -> None:
+    has_subparsers = False
+    for action in parser._actions:
+        if isinstance(action, argparse._SubParsersAction):
+            for choice, child_parser in action.choices.items():
+                has_subparsers = True
+                register_common_flags(child_parser)
+    if not has_subparsers:
+        add_common_flags(parser)
+
+
+def create_parser(prog: str | None = None) -> argparse.ArgumentParser:
+    parser = argparse.ArgumentParser(
+        prog=prog,
+        description="The clan cli tool.",
+        epilog=(
+            """
+Online reference for the clan cli tool: https://docs.clan.lol/reference/cli/
+For more detailed information, visit: https://docs.clan.lol
+        """
+        ),
+        formatter_class=argparse.RawTextHelpFormatter,
+    )
+    add_common_flags(parser)
+
     subparsers = parser.add_subparsers()
 
     parser_backups = subparsers.add_parser(
@@ -285,6 +306,8 @@ For more detailed information, visit: https://docs.clan.lol/getting-started/depl
     if argcomplete:
         argcomplete.autocomplete(parser)
 
+    register_common_flags(parser)
+
     return parser