Add Windows support via Git Bash

[nickknyc]

• Add docs/WINDOWS.md: Comprehensive Windows setup guide

  • Git Bash installation and configuration
  • Dependency installation (jq, pandoc)
  • Path configuration and troubleshooting
  • WSL2 alternative option

• Add scripts/setup-windows.ps1: Automated Windows setup script

  • Detects and installs dependencies via winget/choco/scoop
  • Configures Git Bash PATH automatically
  • Handles jq and pandoc path detection
  • Provides clear setup instructions

• Update README.md: Add Windows to platform badge and prerequisites

  • Include Windows in supported platforms
  • Add Windows setup reference in prerequisites
  • Add WINDOWS.md to documentation list

This enables Polis CLI to run natively on Windows using Git Bash with minimal setup effort. All polis commands work identically to Linux/macOS versions.

Description

Brief description of the changes in this PR.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring (no functional changes)

Related Issues

Fixes #(issue number)

Changes Made

• Change 1
• Change 2
• Change 3

Testing

Describe how you tested these changes:

• Ran cli/tests/run_tests.sh
• Manually tested affected commands
• Tested on [OS/shell version]

Checklist

• My code follows the project's code style (see CONTRIBUTING.md)
• I have updated documentation if needed
• I have updated the CHANGELOG.md if this is a user-facing change
• I have updated checksum files if I modified cli/bin/polis or cli/bin/polis-tutorial
• My changes don't introduce new warnings or errors

Screenshots (if applicable)

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