Uses assert_cmd + tempfile to spin up a fresh vault per test.
Covers init layout, add/list/get mask semantics, rm/restore/purge cycle,
and generate smoke. Adds RELICARIO_TEST_PASSPHRASE env-var hatch in
unlock_interactive and cmd_init so tests don't need a TTY.
Also fixes read_params in session.rs to correctly parse the nested
params.json format (kdf sub-object) rather than trying to deserialize
the whole file as KdfParams.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
