[QA] Preview | Scene reload fails with OperationCanceledException

### 🛠️ **Build version:**
V157

### 📔 **Issue Description:**
When running a scene preview via npm run start, reloading the scene fails — both when triggered via the reload chat command and via the reload button in the UI. The operation throws an unhandled `System.OperationCanceledException` inside the Explorer's reload flow, and the user sees `"Error running command."`

### 👣 **STR:**

1. With the scene shared on this ticket run `npm i `
2. Run `npm run start `
3. Click on the reload button
4. Check exception on the logs of the preview of CH

### ✔️ **Expected Result:**
The scene should dispose cleanly and the new version should load and become active, without throwing an exception.

### ❌ **Actual Result with evidence:**
The reload throws an unhandled OperationCanceledException, logged as:
`[Error] Error running command: System.OperationCanceledException: The operation was canceled.`

### ➗ **Reproduction:**

##### 🔁 Always - (note)

#### 🖥️ **Operative system and additional Notes:**
Unity Engine version: 6000.4.0f1 (8cf496087c8f)
OS: Windows
GPU: NVIDIA GeForce RTX 4050 Laptop GPU (Driver 32.0.15.6614)

This issue happens on both platforms

[Player (54).log](https://github.com/user-attachments/files/30123265/Player.54.log)

[Scene Broken.zip](https://github.com/user-attachments/files/30123465/iLoveZIP_Create.zip)

Reproduce the failure with the shared scene using `npm i` and `npm run start`, then inspect the preview logs. Trace the reload button and reload chat command into the Explorer reload flow and identify where OperationCanceledException escapes. Done means the scene disposes cleanly, the replacement becomes active, and no unhandled cancellation or "Error running command" is logged.

Written by the indexing model from the issue text.