Closes the minor coverage gaps from the final adversarial review:
- org add card/key/totp reject ungranted + unknown collections (pins the
grant gate on the new write paths, which runs before any secret prompt)
- secure-note --body-stdin masks body; totp --secret-stdin round-trips
(completes the --*-stdin matrix for the org surface)
- key-material edit accept-branch round-trip, verified via get --show
Adds run_stdin + create_collection_and_grant fixture helpers and three
acceptance tests for org add card/key/totp. Red until B1/B2 wire the
subcommands (currently: unrecognized subcommand). Asserts org get masks
card number + key material without --show. Edit round-trips land with B3.
