Feat/powershell (#33)
* feat: add Windows PowerShell platform support
- Add PowerShell tool implementation for Windows command execution
- Add platformutil package for runtime OS detection
- Auto-enable PowerShell on Windows, Bash on Unix-like systems
- Update system prompt and config with PowerShell awareness
* feat: integrate PowerShell support across all components
- Add PowerShell tool support in engine and console
- Add PowerShell configuration in agent settings and runtime
- Add PowerShell guard policies for security
- Add PowerShell integration in runtime snapshot and registry
- Fix CI: add shell: bash for Windows runner compatibility
* fix: simplify powershell settings integration
* refactor: share shell execution runner
* fix: align shell metadata and powershell path handling
* docs: sync shell and prompt documentation
* fix: align install config generation with console setup
* refactor: simplify shared config bootstrap
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Co-authored-by: CHEYAN <tetsuya.ueno@outlook.com>