v0.1.1

First-run experience fixes, based on real first-user confusion:

• Drills auto-open in VS Code when no editor is configured
• Explicit 1-2-3 instructions before every editor-based drill
• Typing/pasting code at the terminal prompt now warns instead of silently grading the unedited starter
• Pressing Enter with an unsaved/unchanged solution file asks 'did you save?' before grading
• --version\ now reports the real package version