fix(core): align shell tool description with configured shell

[kkhomej33-netizen]

Summary

• What changed: Updated the shell tool guidance so it describes the same shell wrapper and syntax rules that command execution actually uses.
• Why it changed: Windows command execution can use cmd.exe, Windows PowerShell, PowerShell 7, or Git Bash/MSYS depending on the environment, but the previous tool guidance always described Windows as cmd.exe and included Bash-only syntax in all cases.
• Reviewer focus: Please check that the generated guidance stays accurate for cmd.exe, Windows PowerShell, PowerShell 7, Bash, and Git Bash/MSYS environments without changing command execution behavior.

Validation

• Commands run:

  cd packages/core
  npx vitest run src/tools/shell.test.ts
  npm run typecheck
  npm run build
  git diff --check

• Prompts / inputs used: N/A
• Expected result: The focused shell tool tests pass, TypeScript type checking passes, the core package builds, and the diff has no whitespace errors.
• Observed result: All listed commands completed successfully.
• Quickest reviewer verification path:

  cd packages/core
  npx vitest run src/tools/shell.test.ts

• Evidence (output, logs, screenshots, video, JSON, before/after, etc.):

  ✓ src/tools/shell.test.ts (182 tests)
  Test Files  1 passed (1)
  Tests  182 passed (182)
  
  > @qwen-code/qwen-code-core@0.15.11 typecheck
  > tsc --noEmit
  
  > @qwen-code/qwen-code-core@0.15.11 build
  > node ../../scripts/build_package.js
  Successfully copied files.
  
  git diff --check
  # no output
  

Scope / Risk

• Main risk or tradeoff: This changes model-facing instructions only. The main risk is wording that could overfit one shell variant, especially around PowerShell command sequencing.
• Not covered / not validated: Manual execution on native Windows, Linux, Docker, Podman, and Seatbelt was not performed.
• Breaking changes / migration notes: None.

Testing Matrix

	🍏	🪟	🐧
npm run	✅	⚠️	⚠️
npx	✅	⚠️	⚠️
Docker	N/A	N/A	N/A
Podman	N/A	N/A	N/A
Seatbelt	N/A	N/A	N/A

Testing matrix notes:

• macOS validation covered the focused unit test, typecheck, and core package build.
• Windows and Linux were covered by mocked platform/environment unit tests, not by manual native runs.
• Docker, Podman, and Seatbelt are not involved in this model-facing shell tool description change.

Linked Issues / Bugs

None.