ActiveEffects: Add complete ActiveEffects management system

- New: modules/mournblade-cyd2-effects.js with utility methods for creating, applying, and managing effects
- New: templates/partial-active-effects.hbs for displaying actor effects
- New: templates/partial-item-effects.hbs for displaying item effects
- Update: modules/mournblade-cyd2-config.js with effect configuration (types, attribute keys, categories)
- Update: templates/actor-sheet.hbs and creature-sheet.hbs with Effects tab
- Update: templates/partial-item-nav.hbs with conditional Effects tab
- Update: templates/item-talent-sheet.hbs with Effects tab content
- Update: base-actor-sheet.mjs with effect action handlers (create, edit, delete, toggle)
- Update: base-item-sheet.mjs with effect action handlers and context
- Update: modules/mournblade-cyd2-main.js to import and expose MournbladeCYD2Effects
- Update: lang/fr.json with effect-related translations

Features:
- Support for creating permanent and temporary effects
- Support for attribute modifications (ADR, PUI, CLA, PRE, TRE, etc.)
- Support for health, soul, combat, and adversity modifications
- Support for status effects
- Support for runes (pronounced and traced) effects
- Toggle to enable/disable effects
- Duration tracking (rounds, turns, seconds, combat, scene)
- Display of all active modifications summary

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

lang/fr.json

@@ -71,5 +71,40 @@
     "traced": "Tracée",
     "tracedrune": "Rune tracée",
     "tracerune": "Tracer"
-  }
-}
+  },
+  "EFFECT": {
+    "new": "Nouvel Effet",
+    "edit": "Éditer l'effet",
+    "delete": "Supprimer l'effet",
+    "deleteConfirm": "Supprimer l'effet",
+    "deleteConfirmText": "Êtes-vous sûr de vouloir supprimer cet effet ?",
+    "create": "Créer un effet",
+    "name": "Nom de l'effet",
+    "icon": "Icône",
+    "description": "Description",
+    "changes": "Modifications",
+    "addChange": "Ajouter une modification",
+    "duration": "Durée",
+    "durationType": "Type de durée",
+    "durationValue": "Valeur",
+    "disabled": "Désactivé",
+    "transfer": "Transférer au token",
+    "noDuration": "Aucune (permanent)",
+    "rounds": "Rounds",
+    "turns": "Tours",
+    "seconds": "Secondes",
+    "combat": "Jusqu'à la fin du combat",
+    "scene": "Jusqu'à la fin de la scène",
+    "attribute": "Attribut",
+    "value": "Valeur",
+    "mode": "Mode",
+    "modeAdd": "Ajouter",
+    "modeMultiply": "Multiplier",
+    "modeOverride": "Remplacer",
+    "modeUpgrade": "Améliorer",
+    "modeDowngrade": "Dégrader",
+    "activeEffects": "Effets Actifs",
+    "noActiveEffects": "Aucun effet actif",
+    "effectSummary": "Résumé des modifications",
+    "toggleEffect": "Activer/Désactiver"
+  }