feat: admin/chef/player permission model + leaderless teams + setleader

Commands:
- Drop all short aliases (c/i/t/j/vis/disband/...) — long names only.
- Every /core team <action> now has a crcore.team.<action> permission.
- Three-tier model:
  * Admin (perm only): create, delete, setleader, score
  * Chef (perm + chef-check in execute): add, remove, transfer, visibility, setspawn
  * Player (perm): join, leave, info, list, top
- delete now takes <team> as argument (admin); no more chef-disband shortcut.

New /core team setleader <team> <player>:
- Admin assigns or replaces a team's leader.
- More permissive than transfer: target may not yet be a member (auto-add),
  and works on leaderless teams.

Leaderless teams:
- Team.leaderId is now nullable.
- getLeaderId() and getLeader() return Optional<...>.
- hasLeader() and isLeader(UUID) helpers added.
- New constructors Team(id, name, tag, color [, visibility]) for leaderless.
- TeamService.createTeam overloads without leaderId.
- TeamService.setLeader(teamId, playerId): assigns/replaces leader (auto-adds
  as member if needed). Fires TeamLeadershipTransferEvent with optional old.
- TeamLeadershipTransferEvent.getOldLeaderId() returns Optional<UUID>.
- SqliteTeamRepository: leader_id column no longer NOT NULL.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/diagrams/builtin-commands-diagram.puml

@@ -1,5 +1,5 @@
 @startuml builtin-commands-diagram
-title CR-Core — Default /core team commands
+title CR-Core — Default /core team commands (admin / chef / joueur)
 
 skinparam classAttributeIconSize 0
 hide empty members
@@ -13,7 +13,6 @@ package "fr.luc.crcore.command.builtin" {
 
   class CoreCommand {
     + CoreCommand(teamSvc, playerSvc)
-    # registerDefaults(): void
   }
   CoreCommand --|> BaseCommand
 
@@ -29,44 +28,93 @@ package "fr.luc.crcore.command.builtin" {
       + {static} teamByName(service): ArgumentType<Team>
     }
 
-    class TeamCreateSubCommand {
-      + execute(ctx): CommandResult
+    ' === ADMIN commands (permission seule) ===
+    package "admin" <<Rectangle>> {
+      class TeamCreateSubCommand {
+        perm: crcore.team.create
+        args: name, tag, color, [leader]
+      }
+      class TeamDeleteSubCommand {
+        perm: crcore.team.delete
+        args: <team>
+      }
+      class TeamSetLeaderSubCommand {
+        perm: crcore.team.setleader
+        args: <team> <player>
+      }
+      class TeamScoreSubCommand {
+        perm: crcore.team.score
+        args: <team> <name> <add|set> <value>
+      }
+    }
+
+    ' === CHEF commands (permission + check chef) ===
+    package "chef" <<Rectangle>> {
+      class TeamAddSubCommand {
+        perm: crcore.team.add
+        args: <player>
+      }
+      class TeamRemoveSubCommand {
+        perm: crcore.team.remove
+        args: <player>
+      }
+      class TeamTransferSubCommand {
+        perm: crcore.team.transfer
+        args: <player>
+      }
+      class TeamVisibilitySubCommand {
+        perm: crcore.team.visibility
+        args: <vis>
+      }
+      class TeamSetSpawnSubCommand {
+        perm: crcore.team.setspawn
+      }
+    }
+
+    ' === PLAYER commands ===
+    package "player" <<Rectangle>> {
+      class TeamJoinSubCommand {
+        perm: crcore.team.join
+        args: <team>
+      }
+      class TeamLeaveSubCommand {
+        perm: crcore.team.leave
+      }
+      class TeamInfoSubCommand {
+        perm: crcore.team.info
+        args: [team]
+      }
+      class TeamListSubCommand {
+        perm: crcore.team.list
+      }
+      class TeamTopSubCommand {
+        perm: crcore.team.top
+        args: [score]
+      }
     }
-    class TeamDeleteSubCommand
-    class TeamAddSubCommand
-    class TeamRemoveSubCommand
-    class TeamJoinSubCommand
-    class TeamLeaveSubCommand
-    class TeamInfoSubCommand
-    class TeamListSubCommand
-    class TeamTransferSubCommand
-    class TeamVisibilitySubCommand
-    class TeamScoreSubCommand
-    class TeamTopSubCommand
-    class TeamSetSpawnSubCommand
 
     TeamCreateSubCommand --|> SubCommand
     TeamDeleteSubCommand --|> SubCommand
+    TeamSetLeaderSubCommand --|> SubCommand
+    TeamScoreSubCommand --|> SubCommand
     TeamAddSubCommand --|> SubCommand
     TeamRemoveSubCommand --|> SubCommand
+    TeamTransferSubCommand --|> SubCommand
+    TeamVisibilitySubCommand --|> SubCommand
+    TeamSetSpawnSubCommand --|> SubCommand
     TeamJoinSubCommand --|> SubCommand
     TeamLeaveSubCommand --|> SubCommand
     TeamInfoSubCommand --|> SubCommand
     TeamListSubCommand --|> SubCommand
-    TeamTransferSubCommand --|> SubCommand
-    TeamVisibilitySubCommand --|> SubCommand
-    TeamScoreSubCommand --|> SubCommand
     TeamTopSubCommand --|> SubCommand
-    TeamSetSpawnSubCommand --|> SubCommand
 
     CoreCommand "1" *-- "1" TeamGroupSubCommand : contains
-    TeamGroupSubCommand "1" *-- "13" SubCommand : contains
+    TeamGroupSubCommand "1" *-- "14" SubCommand : contains
   }
 }
 
-note right of CoreCommand
-  Le plugin de jeu downstream
-  remplace une feuille avec :
+note bottom of TeamGroupSubCommand
+  Override d'une feuille :
   core.getCoreCommand()
       .findSubCommand("team")
       .replaceSubCommand("create",