fix(repair): drill explosion to natural group + apply mission rotation

- ExplodedModel.createParts now descends recursively through single
  mesh-bearing wrapper nodes (e.g. Scene > Moto > Eclatement) until
  reaching a node with multiple mesh-bearing children. Previously the
  first wrapper was used as root, so models with extra Empty/group
  parents fell back to flat leaf meshes lerping in local space.
- Add optional modelRotation field on RepairMissionConfig so fragmented
  + repairing models can match the world-space rotation of the source
  inspection model (parked Ebike).
- Ebike mission now uses EBIKE_WORLD_ROTATION_Y/EBIKE_WORLD_SCALE
  directly so the fragmented bike lines up with the parked bike.

src/components/three/gameplay/RepairGame.tsx

@@ -143,6 +143,7 @@ export function RepairGame({
         {step === "fragmented" ? (
           <ExplodableModel
             modelPath={config.modelPath}
+            rotation={config.modelRotation ?? [0, 0, 0]}
             scale={config.modelScale ?? 1}
             split
           />
@@ -160,6 +161,7 @@ export function RepairGame({
           <>
             <ExplodableModel
               modelPath={config.modelPath}
+              rotation={config.modelRotation ?? [0, 0, 0]}
               scale={config.modelScale ?? 1}
               split
               hideNodeNames={brokenNodeNames}

src/data/gameplay/repairMissions.ts

@@ -3,6 +3,10 @@ import type {
   RepairMissionConfig,
   RepairMissionId,
 } from "@/types/gameplay/repairMission";
+import {
+  EBIKE_WORLD_ROTATION_Y,
+  EBIKE_WORLD_SCALE,
+} from "@/data/ebike/ebikeConfig";
 
 const REPAIR_INTERACT_UI_PATH = "/assets/world/UI/interagir.webm";
 const REPAIR_BROKEN_UI_PATH = "/assets/world/UI/cassé.webm";
@@ -20,7 +24,8 @@ export const REPAIR_MISSIONS: Record<RepairMissionId, RepairMissionConfig> = {
     description:
       "Repair the damaged cooling module before relaunching the bike",
     modelPath: "/models/ebike/model.gltf",
-    modelScale: 0.3,
+    modelScale: EBIKE_WORLD_SCALE,
+    modelRotation: [0, EBIKE_WORLD_ROTATION_Y, 0],
     stageUiPath: "/assets/world/UI/ebike-mission-notification.webm",
     interactUiPath: REPAIR_INTERACT_UI_PATH,
     brokenUiPath: REPAIR_BROKEN_UI_PATH,

src/types/gameplay/repairMission.ts

@@ -64,6 +64,13 @@ export interface RepairMissionConfig {
   description: string;
   modelPath: string;
   modelScale?: ModelTransformProps["scale"];
+  /**
+   * World-space rotation applied to the model when mounted by RepairGame
+   * (fragmented + repairing steps). Should match the rotation used by the
+   * source object in the world (e.g. parked Ebike) so the fragmented model
+   * lines up visually with the inspection model.
+   */
+  modelRotation?: Vector3Tuple;
   stageUiPath: string;
   interactUiPath: string;
   brokenUiPath: string;

src/utils/three/ExplodedModel.ts

@@ -53,13 +53,23 @@ export class ExplodedModel {
   }
 
   private createParts(model: THREE.Object3D): ExplodedPart[] {
-    const root =
-      model.children.length === 1 && model.children[0]
-        ? model.children[0]
-        : model;
-    const directChildren = root.children.filter((child) => hasMesh(child));
+    // Drill down through single-mesh-bearing branches until we find a node
+    // with multiple mesh-bearing children (the natural "explosion group" the
+    // modeler authored). Falls back to flat mesh list only if no such group
+    // exists. This avoids exploding leaves in local space when wrapper nodes
+    // (e.g. "Empty" + "Moto" > "Eclatement") sit above the actual group.
+    let current = model;
+    while (true) {
+      const meshChildren = current.children.filter((child) => hasMesh(child));
+      if (meshChildren.length === 1 && meshChildren[0]) {
+        current = meshChildren[0];
+        continue;
+      }
+      break;
+    }
+    const directChildren = current.children.filter((child) => hasMesh(child));
     const sourceObjects =
-      directChildren.length > 1 ? directChildren : getMeshes(root);
+      directChildren.length > 1 ? directChildren : getMeshes(current);
 
     if (sourceObjects.length === 0) return [];