Add reviewed automatic-answer questions to FAQ

[MrAlders0n]

Summary

• Add five reviewed FAQ answers for observer setup, repeater visibility, Passive mode, region boundaries, and multiregion requests.
• Clarify the existing region administrator answer.
• Keep each answer short and link to the detailed wiki guide.

Verification

• Checked the new claims against the relevant guides and server source.
• mkdocs build --strict passed.
• Confirmed the rendered FAQ contains all eight reviewed questions used by the bot pilot.

The bot change that reads these published answers will be reviewed separately. Please publish this wiki update before deploying that bot change.