Add transport system, fix NPC spawning, and improve water rendering

Transport System (Phases 1-7):
- Implement TransportManager with Catmull-Rom spline path interpolation
- Add WMO dynamic transforms for moving transport instances
- Implement player attachment via world position composition
- Add test transport with circular path around Stormwind harbor
- Add /transport board and /transport leave console commands
- Reuse taxi flight spline system and external follow camera mode

NPC Spawn Fixes:
- Add smart ocean spawn filter: blocks land creatures at high altitude over water (Z>50)
- Allow legitimate water creatures at sea level (Z≤50) to spawn correctly
- Fixes Elder Grey Bears, Highland Striders, and Plainscreepers spawning over ocean
- Snap online creatures to terrain height when valid ground exists

NpcManager Removal:
- Remove deprecated NpcManager (offline mode no longer supported)
- Delete npc_manager.hpp and npc_manager.cpp
- Simplify NPC animation callbacks to use only creatureInstances_ map
- Move NPC callbacks to game initialization in application.cpp

Water Rendering:
- Fix tile seam gaps caused by per-vertex wave randomization
- Add distance-based blending: seamless waves up close (<150u), grid effect far away (>400u)
- Smooth transition between seamless and grid modes (150-400 unit range)
- Preserves aesthetic grid pattern at horizon while eliminating gaps when swimming

include/game/transport_manager.hpp

@@ -0,0 +1,73 @@
+#pragma once
+
+#include <cstdint>
+#include <vector>
+#include <unordered_map>
+#include <glm/glm.hpp>
+#include <glm/gtc/quaternion.hpp>
+
+namespace wowee::rendering {
+    class WMORenderer;
+}
+
+namespace wowee::game {
+
+struct TransportPath {
+    uint32_t pathId;
+    std::vector<glm::vec3> waypoints;  // Position keyframes
+    std::vector<glm::quat> rotations;  // Optional rotation keyframes
+    bool looping;
+    float speed;  // units/sec (default 18.0f like taxi)
+};
+
+struct ActiveTransport {
+    uint64_t guid;              // Entity GUID
+    uint32_t wmoInstanceId;     // WMO renderer instance ID
+    uint32_t pathId;            // Current path
+    size_t currentSegment;      // Current waypoint index
+    float segmentProgress;      // Distance along segment
+    glm::vec3 position;         // Current world position
+    glm::quat rotation;         // Current world rotation
+    glm::mat4 transform;        // Cached world transform
+    glm::mat4 invTransform;     // Cached inverse for collision
+
+    // Player attachment (single-player for now)
+    bool playerOnBoard;
+    glm::vec3 playerLocalOffset;
+
+    // Optional deck boundaries
+    glm::vec3 deckMin;
+    glm::vec3 deckMax;
+    bool hasDeckBounds;
+};
+
+class TransportManager {
+public:
+    TransportManager();
+    ~TransportManager();
+
+    void setWMORenderer(rendering::WMORenderer* renderer) { wmoRenderer_ = renderer; }
+
+    void update(float deltaTime);
+    void registerTransport(uint64_t guid, uint32_t wmoInstanceId, uint32_t pathId);
+    void unregisterTransport(uint64_t guid);
+
+    ActiveTransport* getTransport(uint64_t guid);
+    glm::vec3 getPlayerWorldPosition(uint64_t transportGuid, const glm::vec3& localOffset);
+    glm::mat4 getTransportInvTransform(uint64_t transportGuid);
+
+    void loadPathFromNodes(uint32_t pathId, const std::vector<glm::vec3>& waypoints, bool looping = true, float speed = 18.0f);
+    void setDeckBounds(uint64_t guid, const glm::vec3& min, const glm::vec3& max);
+
+private:
+    void updateTransportMovement(ActiveTransport& transport, float deltaTime);
+    glm::vec3 interpolatePath(const TransportPath& path, size_t segmentIdx, float t);
+    glm::quat calculateOrientation(const TransportPath& path, size_t segmentIdx, float t);
+    void updateTransformMatrices(ActiveTransport& transport);
+
+    std::unordered_map<uint64_t, ActiveTransport> transports_;
+    std::unordered_map<uint32_t, TransportPath> paths_;
+    rendering::WMORenderer* wmoRenderer_ = nullptr;
+};
+
+} // namespace wowee::game