feat(frontend): c2 tasks panel + history import (sprint 8 phase 2)

- Add getC2Tasks / listCallbackHistory / importC2 API functions + types
- useC2Tasks with 2500ms polling (stops when all tasks completed)
- useC2CallbackHistory, useImportC2 hooks
- C2TaskStatusBadge, C2TasksPanel (expandable output rows, polling indicator)
- C2CallbackPicker extracted as shared component (reused in both modals)
- ImportC2HistoryModal: 2-step callback picker → paginated history table
- SimulationFormPage: RT card + tasks panel share left grid column; Import C2 history button
- 37 new tests (api/c2, C2TasksPanel, ImportC2HistoryModal, SimulationFormPage panel visibility)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/hooks/useC2.ts

@@ -3,11 +3,19 @@ import {
   deleteC2Config,
   executeC2,
   getC2Config,
+  getC2Tasks,
+  importC2,
+  listCallbackHistory,
   listCallbacks,
   putC2Config,
   testC2Config,
 } from '@/api/c2';
-import type { C2ConfigInput, C2ExecuteInput } from '@/api/types';
+import type {
+  C2ConfigInput,
+  C2ExecuteInput,
+  C2ImportInput,
+  C2TasksResponse,
+} from '@/api/types';
 
 function c2ConfigKey(engagementId: number) {
   return ['c2-config', engagementId] as const;
@@ -17,6 +25,14 @@ function c2CallbacksKey(engagementId: number) {
   return ['c2-callbacks', engagementId] as const;
 }
 
+function c2TasksKey(simulationId: number) {
+  return ['c2-tasks', simulationId] as const;
+}
+
+function c2HistoryKey(engagementId: number, callbackDisplayId: number, page: number, pageSize: number) {
+  return ['c2-history', engagementId, callbackDisplayId, page, pageSize] as const;
+}
+
 function simulationKey(id: number) {
   return ['simulations', id] as const;
 }
@@ -69,6 +85,22 @@ export function useC2Callbacks(engagementId: number | undefined, options?: { ena
   });
 }
 
+export function useC2Tasks(simulationId: number | undefined, options?: { enabled?: boolean }) {
+  const enabled =
+    typeof simulationId === 'number' &&
+    !Number.isNaN(simulationId) &&
+    (options?.enabled !== false);
+
+  return useQuery({
+    queryKey: simulationId ? c2TasksKey(simulationId) : ['c2-tasks', 'none'],
+    queryFn: () => getC2Tasks(simulationId as number),
+    enabled,
+    // Poll every 2500 ms while any task is incomplete; stop when all done.
+    refetchInterval: (query: { state: { data?: C2TasksResponse } }) =>
+      query.state.data?.tasks?.some((t) => !t.completed) ? 2500 : false,
+  });
+}
+
 export function useExecuteC2(simulationId: number, engagementId: number) {
   const qc = useQueryClient();
   return useMutation({
@@ -76,6 +108,45 @@ export function useExecuteC2(simulationId: number, engagementId: number) {
     onSuccess: () => {
       qc.invalidateQueries({ queryKey: simulationKey(simulationId) });
       qc.invalidateQueries({ queryKey: ['engagements', engagementId, 'simulations'] });
+      qc.invalidateQueries({ queryKey: c2TasksKey(simulationId) });
+    },
+  });
+}
+
+export function useC2CallbackHistory(
+  engagementId: number | undefined,
+  callbackDisplayId: number | null,
+  options?: { page?: number; pageSize?: number; enabled?: boolean },
+) {
+  const page = options?.page ?? 1;
+  const pageSize = options?.pageSize ?? 25;
+  const enabled =
+    typeof engagementId === 'number' &&
+    !Number.isNaN(engagementId) &&
+    callbackDisplayId !== null &&
+    (options?.enabled !== false);
+
+  return useQuery({
+    queryKey:
+      engagementId && callbackDisplayId !== null
+        ? c2HistoryKey(engagementId, callbackDisplayId, page, pageSize)
+        : ['c2-history', 'none'],
+    queryFn: () =>
+      listCallbackHistory(engagementId as number, callbackDisplayId as number, {
+        page,
+        pageSize,
+      }),
+    enabled,
+  });
+}
+
+export function useImportC2(simulationId: number) {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: (input: C2ImportInput) => importC2(simulationId, input),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: c2TasksKey(simulationId) });
+      qc.invalidateQueries({ queryKey: simulationKey(simulationId) });
     },
   });
 }