Support passphrase-protected SSH identity files on non-CLI clients

wiki/bugs.md

@@ -1,4 +1,3 @@
 ## Known Bugs - libmutton
 - On Windows, GPG is sometimes (seems unpredictable) incredibly slow to start (often after a reboot), leading to many operations seemingly hanging
     - **This will be addressed** in the migration off of GPG that will take place before v1.0.0
-- Password-protected SSH identity files currently only prompt for password entry in the CLI, and thus they are not yet supported in GUI/TUI implementations

wiki/developers.md

@@ -15,6 +15,9 @@ These are as follows:
 - `wsl`: Allows creating a Linux binary that can interact with the Windows clipboard (for WSL)
 - `termux`: Allows creating a Linux binary that can interact with the Termux clipboard (for Android)
 
+## Required Global Variable Manipulation
+libmutton provides a `PassphraseInputFunction` global variable that all clients must set to support passphrase-protected SSH identity files. This approach allows for different types of clients (CLI, GUI, TUI) to prompt for the passphrase in the most appropriate way.
+
 ## Required Arguments
 Some arguments should be accepted by all/most libmutton-based password managers. These are as follows:
 - `clipclear`: This argument is required for correct functionality of non-interactive CLI implementations (not needed for interactive GUI/TUI implementations). In order to clear the clipboard on a timer, libmutton-based password managers call another instance of their executable with the `clipclear` argument (e.g. `mutn clipclear`) with the intended clipboard contents provided via STDIN. If after 30 seconds the clipboard contents have not changed, they are cleared. Please accept a `clipclear` argument that calls `core.ClipClearArgument()`.