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/components/issue/queue/ExecutionGroup.test.tsx

@@ -127,7 +127,7 @@ describe('ExecutionGroup', () => {
       render(<ExecutionGroup {...defaultProps} type="parallel" />, { locale: 'en' });
 
       // Parallel items should not have numbers in the numbering position
-      const numberElements = document.querySelectorAll('.text-muted-foreground.text-xs');
+      document.querySelectorAll('.text-muted-foreground.text-xs');
       // In parallel mode, the numbering position should be empty
     });
   });

ccw/frontend/src/components/issue/queue/QueueCard.test.tsx

@@ -17,8 +17,13 @@ describe('QueueCard', () => {
   };
 
   const mockQueue: IssueQueue = {
-    tasks: ['task1', 'task2'],
-    solutions: ['solution1'],
+    tasks: [
+      { item_id: 'task1', issue_id: 'issue-1', solution_id: 'sol-1', status: 'pending', execution_order: 1, execution_group: 'group-1', depends_on: [], semantic_priority: 1 },
+      { item_id: 'task2', issue_id: 'issue-1', solution_id: 'sol-1', status: 'pending', execution_order: 2, execution_group: 'group-1', depends_on: [], semantic_priority: 1 },
+    ],
+    solutions: [
+      { item_id: 'solution1', issue_id: 'issue-1', solution_id: 'sol-1', status: 'pending', execution_order: 1, execution_group: 'group-1', depends_on: [], semantic_priority: 1 },
+    ],
     conflicts: [],
     execution_groups: ['group-1'],
     grouped_items: mockQueueItems,