feat: Implement phases 6 to 9 of the review cycle fix process, including discovery, batching, parallel planning, execution, and completion

- Added Phase 6: Fix Discovery & Batching with intelligent grouping and batching of findings.
- Added Phase 7: Fix Parallel Planning to launch planning agents for concurrent analysis and aggregation of partial plans.
- Added Phase 8: Fix Execution for stage-based execution of fixes with conservative test verification.
- Added Phase 9: Fix Completion to aggregate results, generate summary reports, and handle session completion.
- Introduced new frontend components: ResizeHandle for draggable resizing of sidebar panels and useResizablePanel hook for managing panel sizes with localStorage persistence.
- Added PowerShell script for checking TypeScript errors in source code, excluding test files.

ccw/frontend/src/pages/SessionDetailPage.tsx

@@ -221,7 +221,7 @@ export function SessionDetailPage() {
 
       {activeTab === 'impl-plan' && (
         <div className="mt-4">
-          <ImplPlanTab implPlan={implPlan} />
+          <ImplPlanTab implPlan={implPlan as string | undefined} />
         </div>
       )}