fix(git): expand tilde in SSH identity file paths

[Olshansk]

tl;dr SSH git storage now works on machines where ~/.ssh/config returns identity paths with literal ~.

Summary

• SSH identity file resolution fixed: Tilde (~) in identity file paths is now expanded to the home directory, fixing "no valid authentication method" errors
• Contributing guide added: New docs/guide/contributing.md with copy-paste instructions for building, testing, and verifying changes locally

Table Diff

Component	Before	After
SSH identity file path	Literal ~/.ssh/id_ed25519 passed to go-git (fails)	Expanded to /Users/<user>/.ssh/id_ed25519 via go-homedir
go-homedir usage	Used in local.go only	Also used in git.go for SSH key paths
Contributing docs	N/A	New guide at docs/guide/contributing.md

[Olshansk]

@loderunner Small fix I needed on macOS to sync to github given my ssh key setup.

As an aside - do you plan to depricate this in favor of other projects you're working with?

I personally use 1password but I love the simplicity here.

[loderunner]

This seems like a good addition, and simple implementation too. 👍

Love the cookbook for hackers, too. Just a small docs nit to pick. Fix it and we're good to go.

[loderunner]

@Olshansk thanks for the PR and the continued interest in scrt! I love that you're still using this.

You're right, I should probably deprecate this, I haven't been keeping it up to date.
I still think, like you, that there's something interesting there, but I think it's been superseded by the omnipresence of dotenv, and simple cloud vaults.

If you're using this as a personal vault, though, you might want to take a look at my other project apiki. Has some similarities, but it's meant for personal usage and for environment variables.

I'll try to get your PR merged, and I'd be happy to consider any further contributions.

[loderunner]

I fixed CI on main. Rebase/merge and try again.

[Olshansk]

@loderunner Appreciate the quick response.

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If you're using this as a personal vault, though, you might want to take a look at my other project apiki. Has some similarities, but it's meant for personal usage and for environment variables.

Yea, I saw that you've been spending some time there and will check it out.

I'll try to get your PR merged, and I'd be happy to consider any further contributions.

Synched to HEAD/main. Should be g2g.

I still think, like you, that there's something interesting there, but I think it's been superseded by the omnipresence of dotenv, and simple cloud vaults.

I also use the 1password CLI, but love the simplicity of scrt.

Will keep you posted (if time permits), but might add 1password as a storage option in addition to local/git/s3.

[loderunner]

Alright, passes CI. Just address the comment in the contributing guide and I'll merge it.