* feat: add detail parameter to list/get mental models (#825)
Add a `detail` query parameter (metadata|content|full) to both list and get
mental model endpoints (HTTP + MCP) to control response size. This reduces
payload for agent boot flows and MCP clients where context budget is limited.
Closes#825
* fix: update Rust CLI for optional mental model fields
The generated Rust client now has content/source_query as Option<String>
after the detail parameter was added. Update CLI code to handle optionals.