CI caught test_config_set_usage_marks_placeholders failing on this PR's
new usage line ('Usage: hermes config set [--force] <key> <value>' vs
the previous 'Usage: hermes config set <key> <value>').
The usage change is intentional — it documents the --force escape hatch
this PR adds for bypassing schema validation. Update the assertion to
require the placeholder markers and --force keyword without pinning the
exact wording, so future doc tweaks (e.g. wrapping or color codes) don't
re-break this test.
Confirmed locally: 4/4 placeholder tests pass.
Co-authored-by: Cursor <cursoragent@cursor.com>
Update the unknown-subcommand config help output to use placeholder syntax too,
and extend the placeholder regression tests to cover show_config() and that
fallback help path.
