fix(cli): prevent unwanted defaults

Prevent unwanted defaults for enabled/disabled MCP config parameters.
Root cause: argparse's store_true action defaults to False when flag is not
provided, making 'not provided' indistinguishable from 'explicitly false'.
This caused enabled/disabled parameters to be injected into Omni model even
when user didn't specify them, resulting in unexpected config updates.

Solution: Set default=None for --enabled (Codex) and --disabled (Kiro) flags
so that absence is represented as None and doesn't get included in the Omni
payload.

The fix enables tri-state behavior:
- Omitted flag → None → not added to Omni → not included in host config
- Provided flag → True → added to Omni → included in host config

This prevents unwanted value flips during partial updates and eliminates
false UNSUPPORTED warnings when these flags aren't used.

Author: LittleCoinCoin

hatch/cli_hatch.py

@@ -1671,6 +1671,7 @@ def main():
     mcp_configure_parser.add_argument(
         "--disabled",
         action="store_true",
+        default=None,
         help="Disable the MCP server [hosts: kiro]"
     )
     mcp_configure_parser.add_argument(
@@ -1703,6 +1704,7 @@ def main():
     mcp_configure_parser.add_argument(
         "--enabled",
         action="store_true",
+        default=None,
         help="Enable the MCP server [hosts: codex]"
     )
     mcp_configure_parser.add_argument(