feat(hetzner): faster git push/pull via ssh -A + credential proxy

[madarco]

Replaces the bundle round-trip on Hetzner with a single ephemeral ssh -A exec per RPC. For SSH origins the in-box git uses the host's forwarded ssh-agent; for HTTPS origins a short-lived host-loopback credential proxy is exposed via ssh -R for the duration of the push. Forwarded agent socket / reverse-forwarded port disappear with the SSH session — no persistent credential exposure inside the box. Falls back to the existing bundle path on missing host agent, auth failure, or non-SSH/HTTPS origins. askPrompt() gate is preserved.

Also adds agentbox git box-fetch <box> [refspec...] (Hetzner only) so the host can pull a box's commits over SSH into refs/remotes/agentbox-/* without registering a persistent remote.

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Note

High Risk
Changes how cloud git RPC authenticates (SSH agent forwarding and HTTPS credentials tunneled into the box); mitigated by session-scoped forwarding, loopback-only proxy, and bundle fallback, but still security-sensitive.

Overview
On Hetzner, relay git.push / git.fetch now try a fast path before the existing git-bundle flow: a one-off ssh -A runs git push / git fetch inside the box against origin. SSH remotes use the host’s forwarded agent; HTTPS remotes use a short-lived host loopback credential proxy (host-credential-proxy.ts) exposed into the box via ssh -R, with in-box git using nc as a credential helper. CloudBackend.execWithAgent (optional, with reverseForward) is implemented on Hetzner via sshExecWithAgent. Any transport/auth failure falls back to the bundle path; the askPrompt() gate is unchanged.

Adds agentbox git box-fetch <box> [refspec...] (Hetzner only): host git fetch over per-box SSH into refs/remotes/agentbox-<box-id>/* with no persistent remote. Docs/backlog updated to describe both flows.

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[madarco]

bugbot review

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

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[cursor]

Missing parentheses cause ambiguous operator precedence

Medium Severity

The isFastPathAuthFailure return expression mixes || and && without explicit parentheses: A || B || C && D. JavaScript's && binding tighter than || makes this evaluate as A || B || (C && D), which happens to match the intended behavior. However, this is a well-known readability trap — a future maintainer adding a condition or reordering terms could easily introduce a real logic bug without noticing the implicit grouping. Adding explicit parentheses around the && clause makes the intent unambiguous.

 

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[cursor]

SCP URLs with absolute paths misclassified as non-SSH

Low Severity

The classifyRemoteUrl regex for SCP-like SSH URLs uses [^/] after the colon, rejecting valid URLs like git@host:/absolute/path/to/repo.git. Git treats user@host:/path as a valid SCP-style SSH remote, but this pattern falls through to 'other', causing the fast path to be skipped unnecessarily for users with self-hosted Git servers that use absolute paths. The fallback to the bundle path still works, but the optimization is silently lost.

 

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