docs(design): define tyrant game stories

design/user-stories/us-003-progress-and-purchase-unlocks.md

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+---
+type: User Story
+title: "US-003: Progress and purchase Tyrant unlocks"
+description: Let the Tyrant earn and spend choices by personally defeating the Vigilante.
+status: backlog
+---
+
+# US-003: Progress and purchase Tyrant unlocks
+
+As the **Tyrant**, I want to earn one meaningful choice for defeating the Vigilante so that each reign develops differently.
+
+## Acceptance criteria
+
+- [ ] The Tyrant gains one level and one unlock choice only when personally credited with killing the current Vigilante.
+- [ ] A Vigilante death caused by another player, the environment, or the Vigilante does not level the Tyrant.
+- [ ] Available purchases are Assassin, Fixer, Tamer, roster intelligence, permanent Resistance, and permanent Strength.
+- [ ] Each class or ability can be purchased at most once during a reign.
+- [ ] A menu or command clearly identifies purchased, available, and unavailable choices.
+- [ ] A purchase consumes exactly one unspent choice and cannot be duplicated by retries or concurrent input.
+- [ ] Progress cannot be earned or spent while the game is paused.
+- [ ] Levels, purchases, and unspent choices survive logout and restart but reset when the reign ends.
+
+## Related
+
+- [Role and class model](../concepts/role-and-class-model.md)
+- [Assign unlocked classes](us-004-assign-unlocked-classes.md)
+- [Purchase and use Tyrant abilities](us-009-use-tyrant-abilities.md)