feat(project): show business fields in statistics details

Reuse assignment business columns and keyword searches in the four statistics drill-down lists. Add a statistics-permission read endpoint sharing tenant-scoped detail queries without granting assignment access.

Related to issue #13. Independent static review completed. User self-test arrangement: regression cases authored, no tests or builds executed.

web-admin/src/api/project-management.ts

@@ -91,6 +91,11 @@ export const fetchAssignmentRecords = (params: Record<string, unknown>) =>
     url: `${base}/assignments/records`,
     params
   })
+export const fetchStatisticsRecords = (params: Record<string, unknown>) =>
+  request.get<{ list: AssignmentRecord[]; total: number; statusCounts: Record<string, number> }>({
+    url: `${base}/statistics/records`,
+    params
+  })
 export const previewAssignment = (data: ProjectRecord) =>
   request.post<{ records: ProjectRecord[] }>({ url: `${base}/assignments/preview`, data })
 export const saveAssignment = (data: ProjectRecord) =>