feat(gameplay): implement entity movement system with collision detection

- Add Velocity and HitBoxes components to entity
- Introduce HitboxManager for loading per-entity collision AABBs from JSON
- Create MoveSystem with per-axis collision handling
- Move get_block_aabb to base World class and add virtual get_per_tick_time
- Remove static get_block_aabb from ClientWorld; use member m_per_tick_time for tick duration

src/gameplay/hitbox_manager.cpp

@@ -0,0 +1,63 @@
+#include "Cubed/gameplay/hitbox_manager.hpp"
+
+#include "Cubed/tools/log.hpp"
+
+#include <nlohmann/json.hpp>
+namespace fs = std::filesystem;
+using nlohmann::json;
+namespace Cubed {
+HitboxManager::HitboxManager() {}
+HitboxManager::~HitboxManager() {}
+
+HitboxManager& HitboxManager::instance() {
+    static HitboxManager inst;
+    return inst;
+}
+
+AABB HitboxManager::aabb(const std::string& key) {
+    return instance().get_aabb(key);
+}
+
+AABB HitboxManager::get_aabb(const std::string& key) {
+    {
+        cacc c;
+        if (m_hitboxes.find(c, key)) {
+            return c->second;
+        }
+    }
+
+    return load(key);
+}
+
+AABB HitboxManager::load(const std::string& path) {
+    fs::path p = ASSETS_PATH + path;
+    try {
+        glm::vec3 center;
+        glm::vec3 half;
+        std::ifstream s{p};
+        json j = json::parse(s);
+        if (j.contains("boxes")) {
+            if (j["boxes"].contains("center")) {
+                center.x = j["boxes"]["center"].at(0).get<float>();
+                center.y = j["boxes"]["center"].at(1).get<float>();
+                center.z = j["boxes"]["center"].at(2).get<float>();
+            }
+            if (j["boxes"].contains("half")) {
+                half.x = j["boxes"]["half"].at(0).get<float>();
+                half.y = j["boxes"]["half"].at(1).get<float>();
+                half.z = j["boxes"]["half"].at(2).get<float>();
+            }
+        }
+        acc a;
+        if (m_hitboxes.insert(a, path)) {
+            a->second = AABB{center, half};
+            return a->second;
+        }
+    } catch (const std::exception& e) {
+        Logger::error("Load Hitbox error {}", e.what());
+    }
+    Logger::error("Load hitbox {} Failed", path);
+    return AABB{glm::vec3(0.0f), glm::vec3(0.0f)};
+}
+
+} // namespace Cubed