feat(commands): add contextual tab completion

design/user-stories/index.md

@@ -17,3 +17,4 @@
 15. [US-015: Manage a reign through the Tyrant control panel](us-015-manage-tyrant-control-panel.md)
 16. [US-016: Manage Followers through the Vigilante control panel](us-016-manage-vigilante-control-panel.md)
 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)

design/user-stories/us-018-complete-commands-contextually.md

@@ -0,0 +1,39 @@
+---
+type: User Story
+title: "US-018: Complete Tyrant commands contextually"
+description: Replace Bukkit's player-name fallback with valid context-aware command suggestions.
+status: done
+---
+
+# US-018: Complete Tyrant commands contextually
+
+As a **player or administrator**, I want contextual command suggestions so that I can discover valid Tyrant commands and arguments.
+
+## Acceptance criteria
+
+- [x] `/tyrant` suggests its available subcommands instead of arbitrary player names.
+- [x] `/tyrant buy` suggests Tyrant unlock names.
+- [x] `/tyrant assign` suggests `assassin`, `fixer`, and `tamer`, followed by eligible online players.
+- [x] `/tyrant relinquish` suggests `confirm`.
+- [x] `/vigilante` suggests its available subcommands.
+- [x] `/vigilante invite` suggests eligible online recruitment candidates.
+- [x] `/vigilante dismiss` suggests current online Followers.
+- [x] `/tyrantadmin` suggestions are visible only to senders with `spigottyrant.admin`.
+- [x] `/tyrantadmin start` suggests online Tyrant and Vigilante candidates.
+- [x] `/tyrantadmin reset` suggests `confirm`.
+- [x] Suggestions are filtered case-insensitively by the partially typed argument.
+- [x] Suggestions never include syntactically invalid options for the current argument position.
+- [x] Console completion works for administrative commands without exposing player-only commands as executable console actions.
+- [x] Existing command execution behavior remains unchanged.
+
+## Validation
+
+Automated tests verify root syntax, unlocks, classes, confirmations, eligible recruits, current Followers, permission gating, online administrative candidates, argument positions, and case-insensitive prefix filtering. The complete `./gradlew clean check jar` lifecycle passes.
+
+## Related
+
+- [Start, pause, and administer the game](us-001-start-pause-and-administer.md)
+- [Assign unlocked classes](us-004-assign-unlocked-classes.md)
+- [Support the Vigilante and Followers](us-008-support-vigilante-and-followers.md)
+- [Manage a reign through the Tyrant control panel](us-015-manage-tyrant-control-panel.md)
+- [Manage Followers through the Vigilante control panel](us-016-manage-vigilante-control-panel.md)