feat(stealth): conceal identity for prepared sessions

design/user-stories/us-002-rejoin-without-visible-identity.md

@@ -2,7 +2,7 @@
 type: User Story
 title: "US-002: Rejoin without a visible identity"
 description: Let an unlocked player turn a qualifying invisible disconnect into one identity-concealed session.
-status: backlog
+status: done
 ---
 
 # US-002: Rejoin without a visible identity
@@ -11,18 +11,22 @@ As an **unlocked player**, I want to disconnect while invisibility from a potion
 
 ## Acceptance criteria
 
-- [ ] An unlocked player becomes eligible for a concealed login only by disconnecting while an invisibility effect from a potion they directly drank remains active.
-- [ ] A player who has not unlocked stealth cannot prepare a concealed login.
-- [ ] An ordinary disconnect without an active qualifying effect clears any preparation for the next login.
-- [ ] On a prepared login, no public join announcement is shown.
-- [ ] Throughout the concealed session, the player is absent from every other player's tab list, including administrators' tab lists.
-- [ ] Throughout the concealed session, no overhead name tag identifies the player to any other player, including administrators.
-- [ ] The concealed player's physical character remains visible in the world and retains ordinary movement, interaction, combat, and permission behavior.
-- [ ] The concealed player receives a private message explaining that stealth is active for the session.
-- [ ] Concealment lasts until the player disconnects and is handled predictably across death and plugin reload or disable events.
-- [ ] Disconnecting consumes the current concealed session; another concealed login requires another qualifying potion and qualifying disconnect.
-- [ ] Merely owning the unlock never conceals an ordinary login or carries concealment automatically into a later session.
-- [ ] Prepared-login state survives a server restart between the qualifying disconnect and the next login.
+- [x] An unlocked player becomes eligible for a concealed login only by disconnecting while an invisibility effect from a potion they directly drank remains active.
+- [x] A player who has not unlocked stealth cannot prepare a concealed login.
+- [x] An ordinary disconnect without an active qualifying effect clears any preparation for the next login.
+- [x] On a prepared login, no public join announcement is shown.
+- [x] Throughout the concealed session, the player is absent from every other player's tab list, including administrators' tab lists.
+- [x] Throughout the concealed session, no overhead name tag identifies the player to any other player, including administrators.
+- [x] The concealed player's physical character remains visible in the world and retains ordinary movement, interaction, combat, and permission behavior.
+- [x] The concealed player receives a private message explaining that stealth is active for the session.
+- [x] Concealment lasts until the player disconnects and is handled predictably across death and plugin reload or disable events.
+- [x] Disconnecting consumes the current concealed session; another concealed login requires another qualifying potion and qualifying disconnect.
+- [x] Merely owning the unlock never conceals an ordinary login or carries concealment automatically into a later session.
+- [x] Prepared-login state survives a server restart between the qualifying disconnect and the next login.
+
+## Validation
+
+Automated tests verify unlocked and locked disconnect transitions, ordinary-disconnect clearing, one-login consumption, announcement suppression, private activation messaging, ordinary-login presentation, tab removal for existing and new observers, overhead-name suppression, and the absence of entity-hiding calls. ProtocolLib is declared as a required dependency, prepared state round trips through YAML, and `./gradlew clean check jar` passes.
 
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