Features added:
- Custom Agent Creator dialog with AI generation support (up to 30k chars)
- Plus button next to agent selector to create new agents
- Zread MCP Server from Z.AI in marketplace (remote HTTP config)
- Extended MCP config types to support remote/http/sse servers
Bug fixes:
- Filter SDK Z.AI/GLM providers to ensure our custom routing with full message history
- This fixes the issue where changing models mid-chat lost conversationcontext
