feat: moderation feature skeleton (/core admin + mod mode + tools)

New feature fr.luc.crcore.features.moderation, opt-in via
CRCoreConfig.setupModeration() (also enabled by setupAll()).

Core abstractions:
- ModerationState: full player snapshot (inv + armor + offhand, XP,
  health, food, location, gamemode, allowFlight/flying, walk/fly speed).
  Immutable, restoreTo(player) restores everything.
- ModerationService interface + ModerationServiceImpl (with
  protected onAfterEnter/onAfterExit hooks) +
  BukkitEventFiringModerationServiceImpl (fires ModerationEnterEvent /
  ModerationExitEvent).
- ModerationRepository interface + InMemoryModerationRepository
  (skeleton — SQLite impl with BukkitObjectOutputStream serialization
  planned).
- ModeratorTool interface: getKey/getSlot(0..8)/buildIcon +
  onLeftClick/onRightClick/onInteractEntity. ModeratorToolRegistry
  preserves registration order, slot collision = replace.
- Exceptions: ModerationException base + AlreadyActive + NotActive.
- Events: ModerationEvent base + Enter + Exit.

5 skeleton tools in the hotbar:
- slot 0: TeleportRandomPlayerTool (compass, right-click → tp random)
- slot 1: InventorySpyTool (chest, right-click on player → open inv)
- slot 2: FreezeTool (ice, right-click on player → toggle freeze)
- slot 7: VanishToggleTool (ender eye, click → toggle vanish)
- slot 8: ExitTool (barrier, click → exit mod mode)
Slots 3-6 free for custom tools.

ModerationListener routes interactions and locks hotbar:
- PlayerInteractEvent → tool.onLeftClick / onRightClick (with cancel).
- PlayerInteractEntityEvent → tool.onInteractEntity (with cancel).
- PlayerDropItemEvent / PlayerSwapHandItemsEvent: cancel for mods.
- InventoryClickEvent: cancel only when top inv is the mod's own inv
  (preserves InventorySpyTool's ability to manipulate target's inv).
- PlayerJoinEvent: re-applies vanish for already-vanished mods.
- PlayerQuitEvent: cleanup freeze state.
- PlayerMoveEvent: cancel block-position changes for frozen players,
  keeping head rotation free.

Mod mode lifecycle:
- enter: snapshot + clear inv + populate hotbar + CREATIVE +
  allowFlight + vanish + ModerationEnterEvent.
- exit: state.restoreTo(player) + unvanish + unfreeze + repo delete +
  ModerationExitEvent.

/core admin (perm crcore.admin, player-only): toggle on/off.
Messages moderation.enter.success / moderation.exit.success added
to crcore-messages.yml.

CRCoreConfig.setupModeration() + isModerationEnabled() flag.
CRCore: buildModerationService() and registerDefaultModeratorTools()
override points, moderation() / getModerationService() getters with
IllegalStateException guard. Builds + registers ModerationListener at
enable() when feature on. CoreCommand extended to take ModerationService;
registers AdminToggleSubCommand only when service non-null.

Skeleton limitations documented in features.md:
- In-memory repo only (server crash = lost inv) — SQLite planned.
- InventorySpyTool opens real inv (no read-only wrapping yet).
- TeleportRandomPlayerTool is a placeholder for a future player-picker
  GUI.
- No moderation.*.broadcast keys yet.
- No /core admin <player> (self-toggle only).

Docs: section 11 in features.md, decision logged in decisions.md
(skeleton scope + rationale), setup.md snippet updated,
new moderation-class-diagram.puml, README.md updated.

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

docs/decisions.md

@@ -367,6 +367,45 @@ Format léger : une décision = un titre + contexte + choix + raison.
   bases existantes, ALTER TABLE manuel ou suppression du fichier
   (les bases d'event sont jetables).
 
+## 2026-06-10 — Feature modération (skeleton)
+
+- **Choix** : nouveau module `fr.luc.crcore.features.moderation`,
+  opt-in via `CRCoreConfig.setupModeration()`. Skeleton complet :
+  - `ModerationState` (snapshot total : inv, armor, offhand, XP, health,
+    food, location, gamemode, flight/fly speed)
+  - `ModerationService` (interface) + `ModerationServiceImpl` +
+    `BukkitEventFiringModerationServiceImpl` (tire `ModerationEnterEvent`
+    / `ModerationExitEvent`)
+  - `ModeratorTool` interface + `ModeratorToolRegistry`
+  - 5 outils squelette (slots 0, 1, 2, 7, 8) :
+    `TeleportRandomPlayerTool`, `InventorySpyTool`, `FreezeTool`,
+    `VanishToggleTool`, `ExitTool`
+  - `ModerationListener` unique : route les clics → tool, lock hotbar
+    (drop, swap, inventory click sur self), vanish-on-join,
+    freeze (PlayerMoveEvent cancel)
+  - `/core admin` toggle on/off (perm `crcore.admin`, player-only)
+- **Vanish** : `Player.hidePlayer(plugin, vanished)` — propre, sans
+  modif visuelle, pas de fake-quit. Le listener re-applique
+  automatiquement aux joueurs qui join.
+- **Persistance in-memory uniquement** (skeleton). Si le serveur crash
+  pendant qu'un mod est en mod mode, son inventaire est perdu. Une
+  impl `SqliteModerationRepository` avec sérialisation
+  `BukkitObjectOutputStream` → base64 est prévue pour plus tard. Pas
+  bloquant pour la première itération.
+- **Mod mode → CREATIVE + allowFlight** par défaut. Choisi pour la
+  visibilité totale + mobility. Override possible en sous-classant
+  `ModerationServiceImpl.enter()`.
+- **Outils en slots fixes** plutôt qu'avec PersistentDataContainer.
+  Plus simple ; le `ModerationListener` annule tout drop/swap pour
+  garantir que les outils restent en place. Pour identification croisée
+  (NBT) on pourra ajouter plus tard.
+- **Tools extensibles** : `core.moderation().getToolRegistry().register(...)`
+  côté game plugin. Les slots libres (3, 4, 5, 6) sont prêts pour les
+  outils custom.
+- **Listener responsibilities** : un seul `ModerationListener`
+  centralise toutes les hooks (clicks, freeze, vanish, lock hotbar).
+  Évite de disperser dans 5 listeners séparés.
+
 ## 2026-06-10 — Réorganisation : `util/` (toujours) vs `features/` (opt-in)
 
 - **Choix** : séparation nette en deux couches :