feat(scene): keep map tokens with preview rotation

When previewRotationDeg changes, remap non-player, NPC and trap
markers (plus live session token overrides) so they stay on the art.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/main/tokens/sceneTokensSessionStore.ts

@@ -1,4 +1,5 @@
 import type { SceneTokensSessionEvent, SceneTokensSessionState } from '../../shared/types';
+import { rotateMapNormPointByCwSteps } from '../../shared/types/scenePreviewRotation';
 
 function emptyState(): SceneTokensSessionState {
   return {
@@ -23,6 +24,26 @@ export class SceneTokensSessionStore {
     return this.state;
   }
 
+  /** Rotate session position overrides with the scene preview (CSS rotate steps). */
+  rotateMapCwSteps(steps: number): SceneTokensSessionState {
+    const n = ((steps % 4) + 4) % 4;
+    if (n === 0) return this.state;
+    const ids = Object.keys(this.state.byPlacementId);
+    if (ids.length === 0) return this.state;
+    const byPlacementId: SceneTokensSessionState['byPlacementId'] = {};
+    for (const id of ids) {
+      const prev = this.state.byPlacementId[id];
+      if (!prev) continue;
+      const next = rotateMapNormPointByCwSteps(prev.nx, prev.ny, n);
+      byPlacementId[id] = { nx: next.nx, ny: next.ny };
+    }
+    this.state = {
+      revision: this.state.revision + 1,
+      byPlacementId,
+    };
+    return this.state;
+  }
+
   dispatch(event: SceneTokensSessionEvent): SceneTokensSessionState {
     switch (event.kind) {
       case 'clear':