- Introduce new `owlen-markdown` crate that converts Markdown strings to `ratatui::Text` with headings, lists, bold/italic, and inline code.
- Add `render_markdown` config option (default true) and expose it via `app.render_markdown_enabled()`.
- Implement `:markdown [on|off]` command to toggle markdown rendering.
- Update help overlay to document the new markdown toggle.
- Adjust UI rendering to conditionally apply markdown styling based on the markdown flag and code mode.
- Wire the new crate into `owlen-tui` Cargo.toml.
Introduce `DetailedModelInfo` and `ModelInfoRetrievalError` structs for richer model data.
Add `ModelDetailsCache` with TTL‑based storage and async API for get/insert/invalidate.
Extend `OllamaProvider` to fetch, cache, refresh, and list detailed model info.
Expose model‑detail methods in `Session` for on‑demand and bulk retrieval.
Add `ModelInfoPanel` widget to display detailed info with scrolling support.
Update TUI rendering to show the panel, compute viewport height, and render model selector labels with parameters, size, and context length.
Adjust imports and module re‑exports accordingly.