feat: mount user ssh folder for git authentication

[kemingy]

Description

When developing in the container, users may want to submit the commits. But it will fail because there is no public/private key there.

 ⬢ [envd]❯ git push --set-upstream origin add_envd
The authenticity of host 'github.com (XXXXXXXXXXX)' can't be established.
ECDSA key fingerprint is SHA256:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.
Are you sure you want to continue connecting (yes/no/[fingerprint])?
Host key verification failed.
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

mosec on git add_envd [$] is 📦 v0.4.5 via Py v3.9.16 via 🦀 v1.66.1 via 🅒  envd took 3s
[128:] ⬢ [envd]❯ ls $HOME/.ssh

⬢ [envd]❯

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[gaocegege]

It should work with the agent forwarding. Thus it is not a feature, it should be a bug.