Core/Spells: Define spell effect attributes

src/server/game/DataStores/DBCEnums.h

@@ -1288,6 +1288,16 @@ enum SpellCategoryFlags
     SPELL_CATEGORY_FLAG_COOLDOWN_EXPIRES_AT_DAILY_RESET     = 0x08
 };
 
+enum class SpellEffectAttributes
+{
+    None                                    = 0,
+    UnaffectedByInvulnerability             = 0x000001, // not cancelled by immunities
+    NoScaleWithStack                        = 0x000040,
+    StackAuraAmountOnRecast                 = 0x008000, // refreshing periodic auras with this attribute will add remaining damage to new aura
+    AllowAnyExplicitTarget                  = 0x100000,
+    IgnoreDuringCooldownTimeRateCalculation = 0x800000
+};
+
 #define MAX_SPELL_EFFECTS 32
 #define MAX_EFFECT_MASK 0xFFFFFFFF