Document findings from database investigation:
- Session table schema with all fields explained
- Session ID format and generation (unique, no duplicates)
- Parent-child relationships for forked sessions
- Session detection logic used by kugetsu
- Permission structure and common issues
- SQL queries for debugging session problems
- Known issues and solutions (from #81, #36)
This document helps future debugging of session-related issues
without having to investigate opencode internals directly.
