Added

• VS Code: auto-detect outdated cha binary — prompt update when version mismatches extension
• VS Code: debug logs in ensureBinary for diagnostics
• VS Code e2e: real VS Code test on 3 platforms (ubuntu/macos/windows) with sinon stub for user Download click

Fixed

• SDK macros: include build.rs in package
• VS Code: Windows download (.zip + PowerShell + .exe)
• VS Code: exclude test files from .vsix via .vscodeignore
• CI: vscode e2e set continue-on-error for network flakiness