Impossible to use vscode in one of my (oldest) workspace without `chat.disableAIFeatures` being set

- Copilot Chat Extension Version: 0.64.1
- VS Code Version: 1.136
- OS Version: Ubuntu 24.04
- Feature (e.g. agent/edit/ask mode): Anything
- Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): Any
- Logs: Impossible to catch

Steps to Reproduce:

1. Open a workspace (with multiple projects in it, that I've been using for some years)
2. Hang
3. Wait for 10 minutes
4. vscode works again
5. Randomly will hang again
6. Wait again... repat!

```
2026-09-16 15:18:48.956 [info] [GitExtensionServiceImpl] Initializing Git extension service.
2026-09-16 15:18:48.956 [info] FetcherService: Experimentation service not available yet, using default fetcher configuration.
2026-09-16 15:18:48.956 [info] Using the Electron fetcher.
2026-09-16 15:18:48.956 [info] [GitExtensionServiceImpl] Successfully activated the vscode.git extension.
2026-09-16 15:18:48.956 [info] [GitExtensionServiceImpl] Enablement state of the vscode.git extension: true.
2026-09-16 15:18:48.956 [info] [GitExtensionServiceImpl] Successfully registered Git commit message provider.
2026-09-16 15:18:48.956 [info] ConversationFeature: Waiting for copilot token or BYOK model to activate conversation feature
2026-09-16 15:18:48.956 [warning] [LanguageModelAccess] LanguageModel/Embeddings are not available without a Copilot token source
2026-09-16 15:18:48.956 [info] [CopilotCLIModels] Skipping model fetch since there is no Copilot token source
2026-09-16 15:18:48.956 [info] BYOK: registered 9 provider(s): ollama, anthropic, gemini, xai, openai, openrouter, azure, customoai, customendpoint
2026-09-16 15:18:48.956 [info] BYOK: fetching known models list
2026-09-16 15:18:48.956 [info] activationBlocker from 'languageModelAccess' took for 64ms
2026-09-16 15:18:48.956 [info] [CopilotCLI] OpenTelemetry enabled: exporter=file, source=github.copilot
2026-09-16 15:18:48.956 [info] BYOK: Copilot Chat known models list fetched successfully.
2026-09-16 15:18:49.014 [info] [CopilotCLI] MCP server started. Lock file: /home/marco/.copilot/ide/460deacd-a6a6-4ad0-ae74-b2b0fd554bf0.lock
2026-09-16 15:18:49.014 [info] [CopilotCLI] Server URI: unix:/tmp/mcp-Vfr8j1/mcp.sock#%2Fmcp
2026-09-16 15:18:49.185 [warning] [LanguageModelAccess] LanguageModel/Embeddings are not available without a Copilot token source
2026-09-16 15:18:49.241 [info] Logged in as 3v1n0
2026-09-16 15:18:50.164 [info] Got Copilot token for 3v1n0
2026-09-16 15:18:50.164 [info] Copilot Chat: 0.64.1, VS Code: 1.136.2
2026-09-16 15:18:50.224 [info] copilot token sku: copilot_for_business_seat_quota
2026-09-16 15:18:50.224 [info] ConversationFeature: Activating contributions
2026-09-16 15:18:50.226 [info] Registering default platform agent...
2026-09-16 15:18:50.228 [info] copilot token sku: copilot_for_business_seat_quota
2026-09-16 15:18:50.229 [info] copilot token sku: copilot_for_business_seat_quota
2026-09-16 15:18:50.229 [info] copilot token sku: copilot_for_business_seat_quota
2026-09-16 15:18:50.231 [info] copilot token sku: copilot_for_business_seat_quota
2026-09-16 15:18:50.232 [info] activationBlocker from 'conversationFeature' took for 1641ms
2026-09-16 15:18:50.233 [info] [context keys] Setting context key: github.copilot-chat.activated
2026-09-16 15:18:50.234 [info] AuthenticationService: firing onDidAuthenticationChange from handleAuthChangeEvent identity change. Has token: true
2026-09-16 15:18:50.234 [info] copilot token sku: copilot_for_business_seat_quota
2026-09-16 15:18:50.245 [info] GithubAvailableEmbeddingTypesManager: Got embeddings. Primary: metis-1024-I16-Binary. Deprecated:
2026-09-16 15:18:50.249 [info] Successfully activated the GitHub.vscode-pull-request-github extension.
2026-09-16 15:18:50.249 [info] [githubTitleAndDescriptionProvider] Initializing GitHub PR title and description provider provider.
2026-09-16 15:18:50.249 [info] Successfully registered GitHub PR title and description provider.
2026-09-16 15:18:50.249 [info] Successfully registered GitHub PR reviewer comments provider.
2026-09-16 15:18:50.249 [info] WorkspaceChunkSearchService: using embedding type metis-1024-I16-Binary
2026-09-16 15:18:50.957 [info] Fetched model metadata in 2338ms 6c0316c5-a967-472a-b62b-7c8d235df163
2026-09-16 15:18:51.382 [info] ConversationFeature: BYOK models available
2026-09-16 15:18:51.382 [info] copilot token sku: copilot_for_business_seat_quota
2026-09-16 15:18:51.386 [info] Latest entry: ccreq:latest.copilotmd
2026-09-16 15:18:51.386 [info] ccreq:eab43a97.copilotmd | markdown
2026-09-16 15:18:54.430 [info] Fetched content exclusion rules for 2 repo(s) in 1460ms
2026-09-16 15:18:54.430 [info] ccreq:76e0bc4b.copilotmd | markdown
2026-09-16 15:18:54.432 [info] Fetched content exclusion rules for 10 repo(s) in 1462ms
2026-09-16 15:18:54.432 [info] ccreq:00fece0b.copilotmd | markdown
2026-09-16 15:18:54.434 [info] Fetched content exclusion rules for 10 repo(s) in 1464ms
2026-09-16 15:18:54.434 [info] ccreq:3d5a1a88.copilotmd | markdown
2026-09-16 15:18:54.481 [info] Fetched content exclusion rules for 10 repo(s) in 1511ms
2026-09-16 15:18:54.481 [info] ccreq:e95c374b.copilotmd | markdown
2026-09-16 15:18:54.501 [info] Fetched content exclusion rules for 10 repo(s) in 1532ms
2026-09-16 15:18:54.501 [info] ccreq:2e55b36d.copilotmd | markdown
2026-09-16 15:21:43.254 [info] [CopilotCLIChatSessionContentProvider] listSessions took 174344.89579900005ms
2026-09-16 15:21:43.254 [info] [CopilotCLIChatSessionContentProvider] listSessions took 174024.20444200002ms
```

`174344ms` to list sesssions does not seems normal.

But in any case during this phase it should NOT block the UI, this should happen in a worker thread. It's really UI development basics.

However I feel that `CopilotCLIChatSessionContentProvider` it's not the mainn problem, as `chat.agentSessions.showExternal: none` did not change the issue, so maybe something else is blocking while we're loading.