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;