Pyquest v0.1.3 — Source-line diagnostics

Failed checks now connect directly back to the editor.

• Exact traceback locations receive red source-line highlights
• Assertion-only failures receive an honest amber related-function highlight
• Every affected gutter line gets a visible diagnostic marker
• Clicking a failed check scrolls and focuses the relevant source line
• Multiple failures remain marked while the selected one is emphasized
• A successful rerun clears all diagnostics