Fixes:
- Added shell:allow-open permission to fix OAuth integration flows
- Added user_id field to ProviderConfig for Custom REST provider CORE ID
- Added UI field for user_id when api_format is custom_rest
- Made userId optional in Custom REST provider requests (only sent if provided)
- Added X-msi-genai-client header to Custom REST provider requests
- Updated CSP to include Custom REST provider domains
- Bumped version to 0.2.6
This fixes:
- OAuth error: 'Command plugin:shell|open not allowed by ACL'
- Missing User ID field in Custom REST provider configuration UI
- Extended ProviderConfig with optional custom fields for non-OpenAI APIs
- Added custom_endpoint_path, custom_auth_header, custom_auth_prefix fields
- Added api_format field to distinguish between OpenAI and Custom REST provider formats
- Added session_id field for stateful conversation APIs
- Implemented chat_custom_rest() method in OpenAI provider
- Custom REST provider uses different request format (prompt+sessionId) and response (msg field)
- Updated TypeScript types to match Rust schema
- Added UI controls in Settings/AIProviders for custom provider configuration
- API format selector auto-populates appropriate defaults (OpenAI vs Custom REST provider)
- Backward compatible: existing providers default to OpenAI format
