Permanently allowed URLs (and other permissions) are not persisted across sessions

### Describe the bug

URL permissions marked as "permanent" (e.g., https://docs.github.com) do not persist across sessions.

### Affected version

GitHub Copilot CLI 1.0.45.

### Steps to reproduce the behavior

Steps to reproduce:

1. In a session, when prompted for URL access, choose "Allow permanently"
2. Start a new session in the same directory
3. The same URL permission is requested again

Root cause observed:
- The permanent choice writes to settings.json → allowedUrls, but permissions-config.json (which appears to be checked at runtime) has no corresponding web_fetch/URL entry. This split causes the permission to be ignored on next session start.

Files involved:
~/.copilot/settings.json (has allowedUrls) vs ~/.copilot/permissions-config.json (has tool_approvals — no URL entry)

### Expected behavior

When a user selects "Allow permanently" for a URL or tool permission, that permission should be respected in all future sessions without prompting again.

### Additional context

_No response_

首先追蹤 settings.json 的 allowedUrls 和 permissions-config.json 的 tool_approvals 如何在工作階段之間寫入和載入。重現永久 URL 核准，然後確認對應的 web_fetch/URL 權限已持久化，並且在新的工作階段中不再要求該權限。

由索引模型根據 Issue 內容生成。