Proposal: document macOS custom pinentry support for Touch ID / Apple Watch workflows

[pppobear]

Hi,

I have been experimenting with rbw on macOS and built a small custom pinentry implementation that works with rbw and uses macOS system authentication before reading a stored password from Keychain.

Project:

• https://github.com/pppobear/pinentry-rbw-macos

What it does:

• plugs into rbw through the existing pinentry configuration
• stores the Bitwarden master password in macOS Keychain
• uses LocalAuthentication before retrieving it
• works with Touch ID
• may also allow Apple Watch when macOS offers it through the system authentication UI

I am not asking for rbw to grow a native biometric implementation.
The current pinentry hook is exactly what made this possible.

What I wanted to ask is:

1. Would you be open to a documentation PR that mentions macOS custom pinentry integrations as a supported/expected extension point?
2. Would you be open to small compatibility/documentation improvements around this workflow if they stay within the existing pinentry model?
3. Is there anything in this area that you would explicitly consider out of scope for rbw?

I am asking first because I saw the maintenance note that the project is largely feature-complete, and I do not want to propose something that goes against the intended scope.

If useful, I can also prepare a short write-up of the rbw interactions this implementation relies on and any rough edges I found while making it work.

If you prefer, I can open a PR limited to documentation only.

Thanks.