Validated wrap->lose->unwrap->restore on a fenced throwaway: the R-recovered key
decrypts a real encrypted snapshot. Pins the PBS-native command sequence (key
change-passphrase --kdf scrypt/none), the pty requirement (F-A1: TTY-only, env var
ignored) + the echo caveat (F-A2: discard pty output so R can't leak), the blob
format/size, and the R format (EFF wordlist, >=128-bit). No K/R/token value recorded.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
