refactor(repair): unify exploded model across phases, simplify ebike flow

- RepairGame: lift a single ExplodableModel mounted across fragmented
  -> done so the model loads once, animates from its real original
  positions, and never re-instantiates between phases. Eliminates the
  position/rotation jumps and re-explosion that occurred when each
  step instantiated its own model.
- ExplodableModel: expose splitSpeed prop so the explode/reassemble
  lerp can be slowed down (REPAIR_FRAGMENT_SPLIT_SPEED = 1.8) for a
  more deliberate visual where each node is seen leaving its origin.
- RepairScanSequence: drop its own ExplodableModel, receive parts
  from the upstream shared instance. Logs the available part names
  when broken-part nodes can't be matched so config drift is visible.
- RepairReassemblyStep: reduced to the completion particles + a
  delayed onSettled callback. The collapse animation is now driven by
  the shared ExplodableModel switching split=false at the reassembling
  phase. After REPAIR_REASSEMBLY_HOLD_MS (1500ms) the upstream flow
  auto-advances to done.
- RepairEbikeRepairTrigger: new minimal interactable for the ebike
  repairing step. Replaces the heavier grabbable-parts UX (cercles,
  ranger pieces) with a single 'Changez le refroidisseur' prompt that
  advances directly to reassembling. Pylon/farm keep RepairRepairingStep.
- RepairCompletionStep: drop the duplicated RepairObjectModel; the
  shared ExplodableModel renders the repaired model at done.
- RepairGame ebike-done: play narrateur_ebikerepare and call
  completeMission on the audio's ended event (with REPAIR_DONE_DIALOGUE_FALLBACK_MS
  fallback). Hands off to pylon without a Validate button.
- EbikeRepairNarrator: drop the done entry; RepairGame owns it now so
  the audio's end event can drive the mission completion handoff.
- RepairGame: drop the window.ebikeParkedPosition livePosition logic.
  Ebike movement is disabled during the repair flow so the static zone
  position is the source of truth, fixing the floating-bike issue
  observed in TestMap.

src/components/game/EbikeRepairNarrator.tsx

@@ -1,8 +1,5 @@
 import { useEffect, useRef } from "react";
-import {
-  EBIKE_REPAIRED_DIALOGUE_ID,
-  EBIKE_SCAN_HINT_DIALOGUE_ID,
-} from "@/data/ebike/ebikeConfig";
+import { EBIKE_SCAN_HINT_DIALOGUE_ID } from "@/data/ebike/ebikeConfig";
 import { useGameStore } from "@/managers/stores/useGameStore";
 import { useSubtitleStore } from "@/managers/stores/useSubtitleStore";
 import type { MissionStep } from "@/types/gameplay/repairMission";
@@ -12,14 +9,13 @@ import { playDialogueById } from "@/utils/dialogues/playDialogue";
 /**
  * Plays narrator cues during the ebike repair game:
  * - `fragmented`  -> "Alors? Pas magnifique ça?... ces galets vont scanner..."
- * - `done`        -> "Eeeet voilà! Il fonctionne comme une horloge!..."
  *
- * The `narrateur_refroidisseur_diagnostic` line is no longer played
- * here on the `repairing` step. It is now triggered by the scan
- * sequence itself when it lands on the refroidisseur node (configured
- * via `RepairMissionPartConfig.voiceLineId` on the broken part). That
- * keeps the audio synchronized with the red broken-part highlight and
- * gates the `scanning -> repairing` transition on the audio's `ended`.
+ * The `narrateur_refroidisseur_diagnostic` line is triggered by the
+ * scan sequence itself when it lands on the refroidisseur node
+ * (configured via `RepairMissionPartConfig.voiceLineId` on the broken
+ * part). The `narrateur_ebikerepare` line is triggered by RepairGame
+ * directly at the `done` step so its `ended` event can drive the
+ * mission completion handoff.
  *
  * Each cue is one-shot per mission run; the played-set resets when the
  * mission state rolls back to `waiting` so debug-panel replays still
@@ -32,7 +28,6 @@ import { playDialogueById } from "@/utils/dialogues/playDialogue";
  */
 const STEP_TO_DIALOGUE_ID: Partial<Record<MissionStep, string>> = {
   fragmented: EBIKE_SCAN_HINT_DIALOGUE_ID,
-  done: EBIKE_REPAIRED_DIALOGUE_ID,
 };
 
 function stopAudio(audio: HTMLAudioElement | null): void {