Extract duplicated metacharacter quoting logic from LocalCommandRunner
and SystemCapability into a shared ShellQuoting static class, following
the established GatewayUrlHelper pattern.
- ShellQuoting.NeedsQuoting: single source of truth for metachar detection
- ShellQuoting.QuoteForShell: shell-aware quoting (cmd vs PowerShell)
- ShellQuoting.FormatExecCommand: display formatting for gateway
- IsShellMetachar: idiomatic switch expression instead of duplicated
multi-case switch blocks
- 43 new unit tests covering all metacharacters, escaping edge cases,
null handling, and both shell modes
Co-authored-by: danedane <1402819+danedane@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
