fix: avoid login flag for csh shells

[mturac]

Summary

• skip the Unix login-shell -l flag when $SHELL points at csh or tcsh
• keep the existing login-shell behavior for bash/zsh-style shells
• cover both the core terminal tool and CLI terminal tool helpers

Fixes #12378

Validation

• npm run build:local-deps --prefix extensions/cli
• npm run vitest --prefix core -- tools/implementations/runTerminalCommand.vitest.ts
• npm test --prefix extensions/cli -- src/tools/runTerminalCommand.test.ts
• npx prettier --check core/tools/implementations/runTerminalCommand.ts core/tools/implementations/runTerminalCommand.vitest.ts extensions/cli/src/tools/runTerminalCommand.ts extensions/cli/src/tools/runTerminalCommand.test.ts

---

Summary by cubic

Skip the Unix login-shell flag for csh/tcsh to prevent command failures, while keeping login behavior for bash/zsh. Applies to both the core terminal tool and the CLI helper. Fixes #12378.

• Bug Fixes
  • Skip -l for csh/tcsh on Unix/macOS and WSL; keep it for bash/zsh; Windows unchanged.
  • Apply logic in both core terminal tool and CLI helper via getShellCommand.
  • Export getShellCommand and add tests to verify csh behavior.

^{Written for commit 5f6ec1f. Summary will update on new commits. Review in cubic}

[github-actions]

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_{Posted by the CLA Assistant Lite bot.}

[cubic-dev-ai]

2 issues found across 4 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="core/tools/implementations/runTerminalCommand.vitest.ts">

<violation number="1" location="core/tools/implementations/runTerminalCommand.vitest.ts:861">
P2: Unix-specific test added without platform guard; will fail on Windows runners</violation>

<violation number="2" location="core/tools/implementations/runTerminalCommand.vitest.ts:869">
P2: Global env cleanup is incorrect when original `SHELL` is undefined; assigning `undefined` to `process.env.SHELL` stringifies it to `'undefined'`, potentially leaking a truthy env value into later tests. Use a conditional restore matching the pattern already used in this file for `HOME` and `USERPROFILE` cleanup.</violation>
</file>

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[mturac]

I have read the CLA Document and I hereby sign the CLA

[mturac]

recheck