feat(tyrant): add arena boss succession

design/user-stories/index.md

@@ -9,7 +9,7 @@
 7. [US-007: Capture and place mobs as a Tamer](us-007-capture-and-place-mobs.md)
 8. [US-008: Support the Vigilante and Followers](us-008-support-vigilante-and-followers.md)
 9. [US-009: Purchase and use Tyrant abilities](us-009-use-tyrant-abilities.md)
-10. [US-010: Handle inactivity and pending selections](us-010-handle-inactivity-and-selection.md)
+10. [US-010: Handle inactivity and arena vacancies](us-010-handle-inactivity-and-selection.md)
 11. [US-011: Inform players and manage participation](us-011-inform-and-manage-participation.md)
 12. [US-012: Configure and persist game state](us-012-configure-and-persist-state.md)
 13. [US-013: Build, test, and release the plugin](us-013-build-test-and-release.md)
@@ -19,3 +19,4 @@
 17. [US-017: Use bound role control items](us-017-use-bound-role-control-items.md)
 18. [US-018: Complete Tyrant commands contextually](us-018-complete-commands-contextually.md)
 19. [US-019: Claim the Vigilante role in the arena](us-019-claim-vigilante-in-arena.md)
+20. [US-020: Claim the Tyrant role in the arena](us-020-claim-tyrant-in-arena.md)