MCP server 'blocked by policy'

### Describe the bug

We have a custom MCP registry which is checked when local MCP servers are configured. Although the local MCP configuration is correct and works just fine within VSCode and IntelliJ plugin, an error message 'MCP server is blocked by policy' is shown.

It is unclear what causes this. The process log mentions the following:
```
2026-06-25T11:40:36.761Z [ERROR] MCP server "io.github.sooperset/mcp-atlassian" filtered: Server "io.github.sooperset/mcp-atlassian" found in registry but local configuration does not match the registered server identity
```

### Affected version

GitHub Copilot CLI 1.0.65

### Steps to reproduce the behavior

1. Configure an MCP server in the mcp-config.json in the ~/.copilot directory or just install it from within the Copilot CLI with `/mcp add`
2. The MCP server is blocked

### Expected behavior

_No response_

### Additional context

_No response_

Riproduci il blocco usando mcp-config.json in ~/.copilot o l’entry point /mcp add, quindi esamina il log del processo per verificare la mancata corrispondenza dell’identità del registro. L’attività è completata quando un server MCP locale configurato correttamente viene accettato invece di essere segnalato come bloccato da una policy.

Scritto dal modello di indicizzazione a partire dal testo della issue.