取消资源画本返回主画布的二次平移动画

新增 returning-main 阶段，区分返回主画布与进入子画布的 transform 过渡。

返回期间取消残留分页事件和进行中的子画布切换，避免返回流程被重新改写。

补充状态机与 appSurface 回归测试，并同步技术方案文档。

apps/ai-game-creator-shell/src/styles.css

@@ -5192,11 +5192,14 @@ iframe.preview-frame {
   transition: none;
 }
 
-.game-resource-book-scene--entering .game-resource-book-scene-world,
-.game-resource-book-scene--returning .game-resource-book-scene-world {
+.game-resource-book-scene--entering .game-resource-book-scene-world {
   transition: transform 420ms cubic-bezier(0.2, 0.78, 0.2, 1);
 }
 
+.game-resource-book-scene--returning-main .game-resource-book-scene-world {
+  transition: none;
+}
+
 .game-resource-book-scene--child {
   pointer-events: auto;
 }
@@ -5471,11 +5474,6 @@ iframe.preview-frame {
     linear-gradient(145deg, #fffdfa 0%, #fff8f2 100%);
 }
 
-.game-resource-book-manager--entering .game-resource-book-main,
-.game-resource-book-manager--returning .game-resource-book-main {
-  transition: transform 420ms cubic-bezier(0.2, 0.78, 0.2, 1);
-}
-
 .game-resource-book-main-heading {
   display: flex;
   align-items: flex-end;

apps/ai-game-creator-shell/src/view/project-development/index.tsx

@@ -2640,6 +2640,13 @@ export default function ProjectDevelopmentView({
         return;
       }
       if (resourceBookState.phase === 'returning') {
+        if (!resourceBookState.pendingCategory) {
+          // A return-to-main transition has no destination category. Ignore
+          // any wheel step that was already queued before the collapse click;
+          // otherwise it can resurrect a child-enter transition and append a
+          // second viewport movement after the return leg.
+          return;
+        }
         // A wheel gesture can arrive while a click-driven book transition is
         // still in flight. Retarget the transition through the same tokenized
         // path so the old timer cannot restore a stale category.
@@ -2661,6 +2668,7 @@ export default function ProjectDevelopmentView({
       cancelResourceCanvasPan,
       cancelResourceCardDrag,
       openResourceBookChild,
+      resourceBookState.pendingCategory,
       resourceBookState.phase,
       resourcePageCategories,
     ],

apps/ai-game-creator-shell/src/view/project-development/resourceBookModel.ts

@@ -1,7 +1,11 @@
 import type { ProjectResourceCategory } from './resourceProjectionModel';
 
 export type ResourceBookCategory = ProjectResourceCategory;
-export type ResourceBookPhase = 'idle' | 'entering' | 'returning';
+export type ResourceBookPhase =
+  | 'idle'
+  | 'entering'
+  | 'returning'
+  | 'returning-main';
 
 export type ResourceBookState = {
   view: 'main' | 'child';
@@ -74,7 +78,7 @@ export function resourceBookReducer(
     case 'finish-transition':
       return state.token === action.token ? { ...state, phase: 'idle' } : state;
     case 'return-to-main':
-      if (state.view !== 'child' || state.phase === 'returning') {
+      if (state.view !== 'child') {
         return state;
       }
       return {
@@ -97,11 +101,10 @@ export function resourceBookReducer(
               view: 'main',
               category: null,
               pendingCategory: null,
-              // Keep the return leg in the animated phase while the scene
-              // viewport transitions from the child viewport back to the
-              // main viewport. The controller dispatches finish-transition
-              // after the same animation window used by child entry.
-              phase: 'entering',
+              // Returning to the main canvas is already completed by the
+              // shared-card shrink leg. Keep a distinct phase so the main
+              // viewport does not receive a second transform transition.
+              phase: 'returning-main',
             }
         : state;
     case 'reset':