test(shell): cover emulated shell branches

[devsy-app]

Package reviewed

pkg/shell (in the pkg-ssh-git scope).

Issue found

pkg/shell had minimal test coverage — a single existing test
(TestRunEmulatedShell_KillExecutesRealBinary) for ~203 lines of code. Three
RunEmulatedShell code paths were exercised only indirectly or not at all:

• the parse-error return when the emulated shell interpreter rejects a
  malformed command
• the custom /dev/null OpenHandler intercept that discards redirected
  output while still running subsequent commands
• the nil env fallback to os.Environ() so referenced variables resolve

Change

Add three focused tests to pkg/shell/shell_test.go (+63 lines, no production
code changes):

• TestRunEmulatedShell_ParseError — feeds a malformed command and asserts a
  parse error is returned.
• TestRunEmulatedShell_DevNullRedirect — redirects output to /dev/null and
  asserts the redirect is intercepted (discarded) while a subsequent visible
  command still runs.
• TestRunEmulatedShell_NilEnvFallsBackToSystem — passes a nil env and
  asserts $HOME resolves via the system environment fallback.

All tests exercise real code paths (no mocks).

Verification performed

• task cli:lint:ci — 0 issues (golangci-lint, new-from-patch vs origin/main).
• task cli:test / go test ./pkg/shell/... — all 4 pkg/shell tests PASS.
• Full suite: only the known pre-existing pkg/git TestRepoClone* failures
  remain (stale assertion on origin/main, unrelated to this change — this PR
  does not touch pkg/git).
• Commit is app-signed and verified (verified=true) via the Devsy GitHub App
  (hack/sign_commit).

This PR was created by an AI agent as part of an automated daily package review job.

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[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Metrics 10 complexity · 0 duplication

Metric	Results
Complexity	10
Duplication	0

View in Codacy

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