[QA] No error notification in Creator Hub when previewing a scene with a runtime error

### 🛠️ **Build version:**
0.44.0-mac-arm64 (PR #1363, Bevy renderer branch)

### 📔 **Issue Description:**
Per the intent of #1380, Creator Hub should show a notification when a scene fails to run. This works correctly for build-time errors (e.g. syntax errors show a "Failed to start preview" toast), but does NOT trigger for runtime errors (errors thrown once the scene script actually executes). In this case, Creator Hub shows no error/warning at all, and Preview proceeds to open Explorer with a silently broken/empty scene.

### 👣 **STR:**
1. Open a scene, enable Bevy Renderer
2. In `src/index.ts`, add: `throw new Error('Intentional test error')`
3. Save, click Preview

### ✔️ **Expected Result:**
Creator Hub should show a notification/toast indicating the scene failed to run, consistent with the existing build-time error handling, before or instead of launching Explorer into a broken scene.

### ❌ **Actual Result with evidence:**
No notification or warning appears in Creator Hub. Preview proceeds normally and opens Explorer, which then loads an empty, non-functional parcel with no indication of the underlying error (see related in-world feedback issue, filed separately, not Bevy-specific).

Screen recording attached: `31.07.2026_17.39.07_REC no error message code error.mp4`

### ➗ **Reproduction:**
##### 🔁 Always - (reproduced consistently)

#### 🖥️ **Operative system and additional Notes:**
macOS, Apple M3 Pro. Confirmed with @nearnshaw as worth reporting.

https://github.com/user-attachments/assets/9b12663e-673c-460d-a4f3-8560750190ec

---------------------------

**Platform update — confirmed reproducing on Windows too**

Retested on Windows 11 using the exact STR from this issue (`throw new Error('Intentional test error')` in `src/index.ts`, Bevy renderer enabled).

Confirmed: no notification/toast appears in Creator Hub when the scene fails to run due to a runtime error. Preview proceeds and opens Explorer with a silently broken/empty scene, same as originally reported on Mac.

**Conclusion:** not platform-specific — reproduces on both macOS (Apple M3 Pro) and Windows 11 (Intel i7-12650H, NVIDIA RTX 4060 Laptop GPU).