docs: Add comprehensive Windows troubleshooting guide

[dhruv1955]

📋 Description

This PR adds a comprehensive Windows troubleshooting guide to the ScanCode Toolkit documentation. The guide addresses common issues that Windows users encounter during installation and setup, based on real experience setting up ScanCode on Windows 11 with Python 3.12.6.

✨ Motivation

During my setup of ScanCode Toolkit on Windows, I encountered several common issues that weren't well-documented:

• PowerShell execution policy blocking scripts
• Virtual environment activation problems
• Python PATH configuration issues
• Long path limitations
• Windows Defender interference

This guide will help future Windows users resolve these issues quickly without needing to search through issue trackers or ask for help.

🔧 Changes Made

• ✅ Created docs/source/getting-started/installation/windows-troubleshooting.rst
• ✅ Added 10 comprehensive troubleshooting sections
• ✅ Included practical PowerShell commands and solutions
• ✅ Added diagnostic script for quick environment checks
• ✅ Updated installation index to include new guide
• ✅ Used proper reStructuredText formatting

📝 Documentation Sections Added

1. PowerShell Execution Policy Issues
2. Virtual Environment Activation Problems
3. Python Not Found Errors
4. Pip Installation Failures
5. Configure Script Failures
6. Long Path Issues
7. Antivirus and Windows Defender
8. Performance Optimization
9. Quick Diagnostic Script
10. Common Error Messages Reference

✅ Testing

• Documentation builds without errors (make html)
• No warnings in Sphinx build output
• New page appears correctly in table of contents
• All code blocks use correct syntax highlighting
• All solutions tested on Windows 11 with Python 3.12.6
• Links and cross-references work correctly

🎯 Target Audience

• New Windows users setting up ScanCode for the first time
• Windows developers encountering environment issues
• Contributors preparing for GSoC or first-time contributions

🔗 Related Issues

This addresses common issues mentioned in:

• Various "Windows setup" related discussions
• First-time contributor questions

✍️ Contributor Checklist

• Documentation follows reStructuredText best practices
• All commands tested on Windows 11
• Solutions verified to work
• Commit message follows contribution guidelines
• Signed-off-by line included in commit
• No breaking changes
• Builds cleanly without warnings

💡 Future Improvements

Potential follow-ups could include:

• Adding similar guides for macOS and Linux
• Creating video walkthroughs
• Adding troubleshooting for WSL2 setups

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Type: Documentation Enhancement
Impact: Improved Windows user experience
Effort: Medium
Risk: None (documentation only)

[dhruv1955]

Hi maintainers! 👋

I've completed the Windows troubleshooting guide and addressed all RST formatting issues. The documentation builds successfully locally with 0 warnings.

However, the core_tests misc_and_scancode check is failing due to what appears to be a CI infrastructure issue:

Build Log Error:

Free memory is lower than 5%; Currently used: 95.23%
No data was written into the file /home/vsts/work/_temp/task_outputs/build_1770794986791.txt

Current Status:

• ✅ 29 out of 31 checks passing
• ✅ All platform tests (Windows, macOS, Linux) passing
• ✅ Documentation builds cleanly with 0 warnings locally
• ✅ All RST formatting corrected
• ❌ 1 test failing with memory/infrastructure error

My Changes:

• Added comprehensive Windows troubleshooting guide (529 lines)
• Updated installation index to include new guide
• Fixed all title underline warnings
• No code changes, documentation only

This appears to be a transient CI failure unrelated to the documentation content. Could you please re-run the failed check or let me know if there's something specific I need to fix?

I'm happy to make any necessary changes - just need guidance on what's needed!