diff promotes m2pack's added/removed/changed/unchanged counts into
data.stats when m2pack reports them as lists or ints. export-runtime-key
follows the real binary's --key/--public-key/--output/--key-id/--format
surface (not the original plan's --pack/--master-key).
Shell out to m2pack-secure with --json, parse its envelope, and
translate into the standard metin-release Result envelope under
data.m2pack. Non-zero exit and non-JSON output map to SubprocessError
with m2pack_failed / m2pack_invalid_json / m2pack_empty_output codes.
Before this change, only the top-level parser defined --json, -v and -q.
Argparse processes arguments left-to-right and hands off to the subparser
after seeing the subcommand name, so the idiomatic
metin-release release inspect --source X --json
failed with 'unrecognized arguments: --json'. Users had to write
metin-release --json release inspect --source X
which is the opposite of what every modern CLI does. Attach a shared
--json/-v/-q flag set to every subparser via a small helper. Same dest
means the last occurrence on the command line wins, which is the intuitive
behaviour. Both placements are now accepted; tests unchanged.
