Document global YAML defaults vs per-agent overrides in settings docs

[rosspeili]

Problem Statement

Per-agent timeout is documented in README and docs/EXAMPLES.md, but it is not obvious that defaults.timeout, defaults.litellm_model, and defaults.temperature in rooms.settings.yaml apply to shipped personas and the orchestrator unless overridden in the wizard. New users may edit only per-agent fields in-session and miss the global settings file.

Proposed Solution

• Add a short subsection (EXAMPLES or ARCHITECTURE): “Global defaults vs per-agent overrides”.
• Include a small table: defaults.litellm_model, defaults.timeout, defaults.temperature, defaults.orchestrator_model, and when the wizard overrides them.
• Cross-link rooms.settings.example.yaml, python cli.py config init, and built-in fallbacks when no file exists.
• No code changes required unless a one-line CLI hint on startup is desired (optional, separate commit).

Alternatives Considered

• Rely on example YAML comments only — insufficient; example file is not read by everyone before first run.
• Duplicate full settings schema in README — too heavy; link to example + one cheat-sheet table is enough.

Priority

Low 🟢

Additional Context

Complements #28; no dependency on presets or auto_select_first issues. Good good-first-issue for contributors comfortable with Markdown only.

[Kangwenqiao]

Hi, I'd like to work on this issue. I'll update the settings documentation with the defaults/overrides table and related links.

[rosspeili]

Thanks @Kangwenqiao, welcome, and thanks for picking this up!

Context: #49 already added docs/SETTINGS.md with YAML keys and a short override rule. What’s still missing for this issue is a clear “Global defaults vs per-agent overrides” subsection users can find quickly (e.g. in docs/EXAMPLES.md and/or a dedicated section in SETTINGS.md).

Direction

• Small table for defaults.litellm_model, defaults.timeout, defaults.temperature, defaults.orchestrator_model.
• Explain: YAML defaults → shipped personas / orchestrator; wizard / persona fields can override for that session.
• Cross-link rooms.settings.example.yaml, python cli.py config init, and “no file = built-in defaults”.

Tips

• Markdown-only; no code changes needed.
• Avoid duplicating the full schema — short cheat-sheet + links is enough.
• Sync with latest main first so you build on the new docs hub.