Changing Code Mode to General Mode

[hujianxin]

In RooCode, Mode is essentially the concept of an Agent. How about changing Code Mode to General Mode (agent)? Then we can integrate the capabilities of the Orchestrator into General Mode, making General Mode the default, powerful, and most commonly used Mode. This would:

1. Simplify the concept of RooCode and reduce the cognitive load on users
2. Empower the most frequently used Mode with greater capabilities