[iPadOS][Codespaces] Webview-based extensions render only in the top ~25% of the sidebar

Does this issue occur when all extensions are disabled?: Yes/No

## Description
Webview-based VS Code extensions are rendered incorrectly in GitHub Codespaces when accessed from iPadOS Safari.
The extension UI is displayed only in approximately the top 25% of the available sidebar height. The remaining approximately 75% of the panel is completely blank.
This affects multiple unrelated Webview-based AI coding-agent extensions, including Roo Code and Kimi, so this does not appear to be specific to a single extension.
The same Codespace and project render these extensions correctly when accessed from Windows 11 + Google Chrome.

## Environment
- Device: iPad
- OS: iPadOS 26.6
- Browser: Safari & Chrome
- Environment: GitHub Codespaces
- VS Code: GitHub Codespaces
- Extension example: Zoo Code
- Roo Code version: 3.58.0

## Reproduction
1. Create or open a GitHub Codespace.
2. Open the Codespace in Safari on an iPad running iPadOS 26.6.
3. Install/enable a Webview-based extension such as Zoo Code, kimi.
4. Open the extension from the Activity Bar / Sidebar.
5. Observe the extension UI.

### Actual result
Only approximately the top 25% of the available Webview area displays the extension UI.
The remaining approximately 75% of the panel is completely blank.

For example:
```text
+--------------------------------+
| |
| Roo Code UI |
| (approximately top 25%) |
| |
+--------------------------------+
| |
| |
| |
| BLANK |
| |
| |
| |
| |
+--------------------------------+

```

### Expected result
The Webview should occupy the full available height of the sidebar, as it does in desktop Chromium browsers.

### Cross-platform comparison
I tested the exact same GitHub Codespace and project on:

- Windows 11 + Google Chrome
- The Webview renders correctly and occupies the expected full height.
- iPadOS 26.6 + Safari
- The Webview is constrained to approximately the top 25% of the available height, with the rest of the panel blank.

This strongly suggests that the issue is related to VS Code for the Web / Webview rendering on iPadOS rather than the individual extension.

###Multiple extensions affected
The issue is reproducible with multiple Webview-based AI coding extensions.
For example:
- Zoo Code
- Kimi extension
- Other AI coding-agent extensions

Because unrelated extensions exhibit the same layout problem, this appears to be a common Webview / browser-mode VS Code issue rather than an extension-specific issue.