feat(Core/Movement): port smooth waypoint movement from Cataclysm Preservation Project (#25106)

Co-authored-by: blinkysc <blinkysc@users.noreply.github.com>
Co-authored-by: Ovahlord <dreadkiller@gmx.de>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: Kitzunu <Kitzunu@users.noreply.github.com>

src/server/game/Entities/Creature/Creature.cpp

@@ -388,6 +388,33 @@ void Creature::SearchFormation()
     }
 }
 
+bool Creature::IsFormationLeader() const
+{
+    if (!m_formation)
+        return false;
+
+    return m_formation->GetLeader() == this;
+}
+
+void Creature::SignalFormationMovement()
+{
+    if (!m_formation)
+        return;
+
+    if (!m_formation->GetLeader() || m_formation->GetLeader() != this)
+        return;
+
+    m_formation->LeaderStartedMoving();
+}
+
+bool Creature::IsFormationLeaderMoveAllowed() const
+{
+    if (!m_formation)
+        return true;
+
+    return m_formation->CanLeaderStartMoving();
+}
+
 void Creature::RemoveCorpse(bool setSpawnTime, bool skipVisibility)
 {
     if (getDeathState() != DeathState::Corpse)

src/server/game/Entities/Creature/Creature.h

@@ -358,6 +358,14 @@ public:
     [[nodiscard]] uint32 GetCurrentWaypointID() const { return m_waypointID; }
     void UpdateWaypointID(uint32 wpID) { m_waypointID = wpID; }
 
+    // nodeId, pathId
+    std::pair<uint32, uint32> GetCurrentWaypointInfo() const { return _currentWaypointNodeInfo; }
+    void UpdateCurrentWaypointInfo(uint32 nodeId, uint32 pathId) { _currentWaypointNodeInfo = { nodeId, pathId }; }
+
+    bool IsFormationLeader() const;
+    void SignalFormationMovement();
+    bool IsFormationLeaderMoveAllowed() const;
+
     void SearchFormation();
     [[nodiscard]] CreatureGroup const* GetFormation() const { return m_formation; }
     [[nodiscard]] CreatureGroup* GetFormation() { return m_formation; }
@@ -519,6 +527,7 @@ private:
     // WaypointMovementGenerator variable
     uint32 m_waypointID;
     uint32 m_path_id;
+    std::pair<uint32, uint32> _currentWaypointNodeInfo{0, 0};
 
     // Formation variable
     CreatureGroup* m_formation;