ssh-add to store ssh passphrase in memory for my session

**Is your feature request related to a problem? Please describe.**
If, for security reason, I have to protect my ssh key with a passphrase I have to enter it every time

**Describe the solution you'd like**
Like Ubuntu OS, the ssh-add command allow me to store the ssh-key for the session avoiding me to enter it anytime. Even if close my terminal.

Start by reproducing the repeated passphrase prompt with ssh-add in a WSL session and compare it with the Ubuntu behavior described in the issue. Identify the WSL component responsible for session-level key storage; done means a key added with ssh-add remains available after closing the terminal without repeated prompts, with the security behavior defined.

Written by the indexing model from the issue text.