Change ListIssues and ListOpenIssues SQL queries to select specific
columns (excluding description, acceptance_criteria, context_refs).
Reduces list API payload size, especially for issues with embedded images.
Frontend handles null description gracefully — board card short-circuits,
issue detail fetches full data via its own query.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>