Feature Request: Support for FIDO2/U2F Hardware Keys via `ssh-add -K`

Device: iPad Air (M4)
OS: 26.4
version: 1.17.5

##### Summary
I am trying to use a FIDO2 hardware security key (CanoKey) for SSH authentication within a-Shell, but the ssh-add -K command fails.

##### Steps to Reproduce
1. Connect CanoKey via USB-C to the iPad.
2. Run `ssh-agent -s`
3. Run `ssh-add -K`

##### Expected Behavior
The agent should interact with the hardware key and load the resident SSH keys (FIDO2/U2F).

##### Actual Behavior
The command returns the following error:
`Cannot download keys without provider`