refactor(physics): rename isSensor to isTrigger (Unity/UE terminology)

UE calls it Trigger (Overlap Events / Trigger preset) and Unity's UI
says "Is Trigger"; "sensor" is the physics-backend term (Jolt sensor,
Box2D sensor). Rename the component/record flag and the Inspector
label. Scene files now persist "IsTrigger" with backward-compatible
read of the old "IsSensor" key.

Engine/src/Physics/PhysicsWorld.cpp

@@ -390,7 +390,7 @@ namespace Engine {
                 rec.halfHeight != halfHeight ||
                 rec.compound != rb.compound ||
                 rec.mass != rb.mass ||
-                rec.isSensor != rb.isSensor) {
+                rec.isTrigger != rb.isTrigger) {
                 // 类型/碰撞体/质量变更 → 重建（简单正确，重置速度可接受）
                 bi.RemoveBody(rec.id);
                 bi.DestroyBody(rec.id);
@@ -860,7 +860,7 @@ namespace Engine {
         settings.mFriction = rb.friction;
         settings.mRestitution = rb.restitution;
         settings.mUserData = entityBits;   // 事件回调：Body → 实体位模式反查
-        settings.mIsSensor = rb.isSensor;  // 传感器：只收 Added/Removed，不解算
+        settings.mIsSensor = rb.isTrigger;  // 触发器：只收 Added/Removed，不解算
 
         const JPH::BodyID id = bi.CreateAndAddBody(
             settings, dynamic ? JPH::EActivation::Activate : JPH::EActivation::DontActivate);
@@ -873,7 +873,7 @@ namespace Engine {
         ExtractShapeParams(rb, rec.radius, rec.halfHeight);
         rec.compound = rb.compound;
         rec.mass = rb.mass;
-        rec.isSensor = rb.isSensor;
+        rec.isTrigger = rb.isTrigger;
         rec.lastPos = tr.GetPosition();
         rec.lastRot = tr.GetRotationQuat();
         m_Bodies[entityBits] = rec;

Engine/src/Serialization/SceneSerializer.cpp

@@ -306,7 +306,7 @@ namespace Engine::Serialization {
                 out << YAML::Key << "Friction" << YAML::Value << rb->friction;
                 out << YAML::Key << "Restitution" << YAML::Value
                     << rb->restitution;
-                out << YAML::Key << "IsSensor" << YAML::Value << rb->isSensor;
+                out << YAML::Key << "IsTrigger" << YAML::Value << rb->isTrigger;
                 // bodyId/bodyValid/velocity 由 PhysicsWorld 对账重建，不存
                 out << YAML::Key << "Active" << YAML::Value << rb->active;
                 out << YAML::EndMap;
@@ -616,7 +616,9 @@ namespace Engine::Serialization {
                 rb.gravityScale = n["GravityScale"].as<f32>(rb.gravityScale);
                 rb.friction = n["Friction"].as<f32>(rb.friction);
                 rb.restitution = n["Restitution"].as<f32>(rb.restitution);
-                rb.isSensor = n["IsSensor"].as<bool>(rb.isSensor);
+                // 新键 IsTrigger；旧场景 IsSensor 兼容读（缺键 as 返回 fallback 安全）
+                rb.isTrigger = n["IsTrigger"].as<bool>(
+                    n["IsSensor"].as<bool>(rb.isTrigger));
                 rb.active = n["Active"].as<bool>(true);
                 // bodyId/bodyValid/velocity 保持默认（对账重建）
             }