Add animation controller system, material assets and skeleton visualization

- .animctrl state machine asset (params/transitions/blend trees, 1D+2D
  directional blending) with Unity Animator-style editor panel: state
  list, transitions, params, directional pad preview driving live
  CrossFade on the selected entity
- Split animation evaluation out of SceneRenderer into
  AnimationSystem/AnimationEvaluator; skin palettes with rest-pose
  fallback and blend-weight epsilon filtering
- MaterialAsset (.material) with reload-safe preview tile pool
  (DropMaterial clears dirty refs before instance destruction)
- EditorGizmoPass skeleton wires + viewport joint overlay; camera
  projection rework (baked Vulkan Y-flip, ortho support)
- Editor/game build split via HELLOVULKAN_EDITOR option

shaders/gizmo_pick.vert

@@ -0,0 +1,21 @@
+#version 450
+
+// Editor gizmo 拾取顶点：与 billboard 共享同一 ring VB（pos/color/aux
+// + entityId 四属性流），画进 HitProxy 的 R32Uint 目标。只有 entityId
+// 参与变换输出，color/aux 声明占位（属性流绑定时全开）。
+
+layout(location = 0) in vec3 inPos;
+layout(location = 1) in vec4 inColor;    // 占位（拾取不用）
+layout(location = 2) in vec4 inAux;      // 占位
+layout(location = 3) in uint inEntityId;
+
+layout(location = 0) flat out uint outEntityId;
+
+layout(push_constant) uniform PC {
+    mat4 viewProj;
+} pc;
+
+void main() {
+    gl_Position = pc.viewProj * vec4(inPos, 1.0);
+    outEntityId = inEntityId;
+}