v3.0.12 🦕 Iguanodon — review fixes: several files at once, print card, safer key files

v3.0.12 🦕 Iguanodon — review fixes: several files at once, print card, safer key files

Follows v3.0.11. Most of this release comes from an external
review by Dean Rie (#48, #50, #51, #54, #55, #45). The cryptography,
container format, wordlist, and self-tests are untouched; the Recovery tool's
decryption core is byte-identical to every release since v2.9.0.

Changes

• Several files at once. Drop more than one file and each is encrypted
  (or decrypted) on its own, with its own salt, and downloaded under its own
  name. A file that fails is named in the summary and does not stop the
  others. (#54)
• Key file fingerprint. A chosen key file shows the first 8 hex
  characters of its SHA-256 next to its name, so the right file can be
  recognised months later. (#54)
• Printable emergency card for encrypted text. One page with the QR, the
  full encrypted text, and three steps to decrypt it. The password is never
  on the card. Decrypted text and seed phrases cannot be printed this way.
  (#55)
• An empty key file is refused. A 0-byte key file adds nothing to the
  key while looking like protection; both pages now say so instead of using
  it. Binary results from text-mode decryption are handed over as a file.
  (#50)
• Accessibility and privacy. Encrypt/Decrypt tabs work with the arrow
  keys; key-file bytes are erased after use; the secret field turns off
  autocomplete, autocorrect and spellcheck; status messages are announced to
  screen readers; nothing secret appears on a printout; reduced-motion
  settings are honoured. (#48, #51)
• CI checks reproducibility. The build now fails if the published pages
  or SHA256SUMS.txt differ from what npm run build produces. (#45)
• Sizes corrected. The Recovery tool is now 30 KB; the READMEs and both
  pages had drifted to older figures. (#59)

For users

Nothing to do. Existing .ibitz files and encrypted text decrypt exactly as
before. If you keep a copy of IttyBitz or the Recovery tool for offline use,
download this release's copy to get the changes above.