DOC: Add comprehensive BUILDGUIDE.md with cross-platform build instructions and VS Code setup#156

Copilot wants to merge 11 commits intomainmicrosoft/mssql-python:mainfrom

copilot/fix-d256ab98-5fb4-49b7-8e63-79159ab0b9b8microsoft/mssql-python:copilot/fix-d256ab98-5fb4-49b7-8e63-79159ab0b9b8Copy head branch name to clipboard