Copilot `fetch failed` to send `google` apikey and to download `claud SDK`

- Copilot Chat Extension Version: 1.0.81-0
- VS Code Version: 1.134.0
- OS Version: WIN10 21H2
- Feature (e.g. agent/edit/ask mode): Add Models in Langage Models, and Agent Host
- Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): N/A
- Logs:
* Failed `fetch failed` to send `google` apikey:
```
exception TypeError: fetch failed sending request: Error: exception TypeError: fetch failed sending request
at c:\Users\user\AppData\Local\Programs\Microsoft VS Code\110a328ea5\resources\app\extensions\copilot\dist\extension.js:1592:154108
at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
at async rkt.list (c:\Users\user\AppData\Local\Programs\Microsoft VS Code\110a328ea5\resources\app\extensions\copilot\dist\extension.js:1592:170758)
at async Ox.getAllModels (c:\Users\user\AppData\Local\Programs\Microsoft VS Code\110a328ea5\resources\app\extensions\copilot\dist\extension.js:1593:3599)
at async Ox.provideLanguageModelChatInformation (c:\Users\user\AppData\Local\Programs\Microsoft VS Code\110a328ea5\resources\app\extensions\copilot\dist\extension.js:1588:7696)
at async ac.$provideLanguageModelChatInfo (file:///c:/Users/user/AppData/Local/Programs/Microsoft%20VS%20Code/110a328ea5/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:546:42424)
```
* Failed to download `claud SDK`:
```
2026-08-19 22:57:24.445 [warning] [AgentService] initial provider catalog for claude was unavailable; retrying before listing sessions Provider claude cannot enumerate its native session catalog yet
2026-08-19 22:57:24.446 [warning] [Claude] SDK unavailable while listing chats to migrate Failed to download claude SDK from https://main.vscode-cdn.net/agent-sdk/claude/0.3.220/win32-x64.tgz (cache target: C:\Users\user\AppData\Roaming\Code\agent-host\sdk-cache\claude\0.3.220\win32-x64). Set VSCODE_AGENT_HOST_CLAUDE_SDK_ROOT to a local SDK root to bypass. Cause: fetch failed
2026-08-19 22:57:24.446 [error] [ProtocolServer] Request 'listSessions' failed Provider claude cannot enumerate its native session catalog yet
```

Steps to Reproduce:

1. Set `http.proxy` "socks5://....:.."
2. Add Models -> Select "google" -> Input apikey -> press enter -> "error" found
2. Happens to see the `Failed to download `claud SDK`` error in debug output `Agent Host`

Additional:
1. The openrouters one has no this issue from the begining.
2. If `http.proxy` was "http://....:.." then it fixs the "fetch failed `google` " issue. Not sure if it also fixs the "download `claud SDK`".

Therefore, the issue looks like to be: the adding "openrouters" and adding "google gemini" used different set of codes. The former one used vscode fetch, and the latter one used nodejs fetch which missed to support socks5 proxy.