treat missing git as inspect-failed instead of not-a-repo

[thedhruvhegde]

summary

any git ExecError was treated as a plain directory. on nixos (and anywhere git is missing from PATH) git exits 127, so a real repo looked like a non-repo.

only exit 128 is "not a git repo". other exec failures stay inspect-failed.

closes #2990

test plan

• PATH without git: opening a git workspace should fail inspect instead of looking like a folder
• a real non-repo directory still inspects as a directory (exit 128)
• normal git workspaces still work

[greptile-apps]

Greptile Summary

This PR narrows workspace inspection’s fallback behavior so that missing Git and most other execution failures become inspect-failed rather than being treated as plain directories.

• Changes the directory fallback from every non-null Git exit code to exit code 128.
• Correctly fixes the missing-executable case, whose ExecError has a null exit code.
• Still treats unrelated Git fatal errors returning 128 as non-repositories.

Confidence Score: 4/5

This PR should not merge until exit-128 Git failures are distinguished from the specific non-repository condition.

Missing Git is now handled correctly, but other fatal Git failures that also return 128 remain silently classified as valid plain directories.

Files Needing Attention: packages/core/src/runtimes/workspace-registry/node/inspect-path.ts

Important Files Changed

Filename	Overview
packages/core/src/runtimes/workspace-registry/node/inspect-path.ts	Narrows Git error classification, but exit code 128 alone does not uniquely identify a non-repository directory.

Prompt To Fix All With AI

### Issue 1
packages/core/src/runtimes/workspace-registry/node/inspect-path.ts:49
**Exit 128 Is Ambiguous**

Git also returns exit code 128 for fatal errors such as permission failures. In those cases, this branch classifies an inaccessible or broken repository as a plain directory instead of `inspect-failed`, so the workspace registry can accept it without surfacing the inspection error. The existing Git runtime avoids this by matching known non-repository messages rather than relying only on the exit code.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "only treat git exit 128 as not-a-repo so..." | Re-trigger Greptile}

[greptile-apps]

Exit 128 Is Ambiguous

Git also returns exit code 128 for fatal errors such as permission failures. In those cases, this branch classifies an inaccessible or broken repository as a plain directory instead of inspect-failed, so the workspace registry can accept it without surfacing the inspection error. The existing Git runtime avoids this by matching known non-repository messages rather than relying only on the exit code.

Prompt To Fix With AI

This is a comment left during a code review.
Path: packages/core/src/runtimes/workspace-registry/node/inspect-path.ts
Line: 49

Comment:
**Exit 128 Is Ambiguous**

Git also returns exit code 128 for fatal errors such as permission failures. In those cases, this branch classifies an inaccessible or broken repository as a plain directory instead of `inspect-failed`, so the workspace registry can accept it without surfacing the inspection error. The existing Git runtime avoids this by matching known non-repository messages rather than relying only on the exit code.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.