feat: add terminal panel components and Zustand store for state management

- Created a barrel export file for terminal panel components.
- Implemented Zustand store for managing terminal panel UI state, including visibility, active terminal, view mode, and terminal ordering.
- Added actions for opening/closing the terminal panel, setting the active terminal, changing view modes, and managing terminal order.
- Introduced selectors for accessing terminal panel state properties.

ccw/frontend/src/hooks/useSkills.ts

@@ -9,7 +9,6 @@ import {
   enableSkill,
   disableSkill,
   type Skill,
-  type SkillsResponse,
 } from '../lib/api';
 import { useWorkflowStore, selectProjectPath } from '@/stores/workflowStore';
 import { workspaceQueryKeys } from '@/lib/queryKeys';