Pull the top-level + chat parser construction out of main() into
hermes_cli/_parser.py so relaunch.py can introspect parser._actions to
discover which flags exist and whether they take values, instead of
maintaining a parallel hand-rolled (flag, takes_value) tuple list.
- _parser.py: build_top_level_parser() returns (parser, subparsers,
chat_parser); side-effect-free import.
- main.py: ~290 lines of inline parser construction collapsed to a
helper call. Other subparsers stay inline (dispatch is bound to
module-level cmd_* functions).
- test_ignore_user_config_flags.py: brittle inspect.getsource grep
replaced with proper parser introspection.
- test_relaunch.py: introspection sanity tests added.
- _parser._inherited_flag(parser, ...): wraps parser.add_argument and
sets action.inherit_on_relaunch = True. Used in place of
parser.add_argument for the 25 flags (top-level + chat) that need to
carry over.
- _parser.PRE_ARGPARSE_INHERITED_FLAGS: holds --profile/-p, which
isn't on argparse (consumed earlier by main._apply_profile_override).
- relaunch.py: drops _CRITICAL_DESTS and _PRE_ARGPARSE_FLAGS; the table
builder now filters by getattr(action, "inherit_on_relaunch", False).
Renames _CRITICAL_FLAGS_TABLE / _build_critical_flag_table /
_extract_critical_flags / preserve_critical= → _INHERITED_FLAGS_TABLE
/ _build_inherited_flag_table / _extract_inherited_flags /
preserve_inherited= so the terminology is consistent.
