README: open with the two-independent-secrets-into-KDF thesis; reframe the
second factor as pluggable (reference image or key file); keep the stego
deep-dive as a distinctive option; update all scenario tables, recovery section,
env-var hint, and roadmap line to use "second-factor secret" language.
docs/CRYPTO.md: add "Pluggable second-factor containers" subsection explaining
that the 32-byte input to Argon2id is identical regardless of container;
reference-image / key-file / recovery-QR are interchangeable carriers.
Update org-vs-personal comparison table and entropy labels.
docs/FORMATS.md: document the .relkey armor format (relicario-keyfile-v1 +
base64 line) and the params.json second_factor field ("image"|"keyfile",
absent means "image" for back-compat). Cite crates/relicario-core/src/keyfile.rs
keyfile_encode/keyfile_decode with TODO-pin comments. Update KDF input formula
from image_secret to second_factor_secret.
DESIGN.md: split secrets-map "Reference image bytes" row to distinguish image
and key-file containers; add key-file row noting keyfileBase64 in
chrome.storage.local has the same in-the-clear posture as imageBase64.
Update vault-layout note and KDF conventions row.
docs/SECURITY.md: add "Second-factor storage posture" subsection explicitly
stating .relkey and keyfileBase64 are the second factor in the clear — same
posture as the reference JPEG / imageBase64, not weaker, protected by the
passphrase invariant. Add RELICARIO_KEYFILE to the env-var trust surface table.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014THSV6cA4Gxa7bxFfisHBB
1591fc7825