docs/reference/tier-system.md:
- Rewritten tier table: free tier now described as "AI unlocks with BYOK"
- New BYOK section explaining the policy and rationale
- Feature gate table gains BYOK-unlocks? column
- API reference updated: can_use, tier_label, has_configured_llm with examples
- "Adding a new feature gate" guide updated to cover BYOK_UNLOCKABLE
demo/config/user.yaml:
- Reformatted by YAML linter; added dismissed_banners for demo UX