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/tests/api/c2.test.ts

@@ -5,6 +5,9 @@ import {
   deleteC2Config,
   executeC2,
   getC2Config,
+  getC2Tasks,
+  importC2,
+  listCallbackHistory,
   listCallbacks,
   putC2Config,
   testC2Config,
@@ -134,3 +137,63 @@ describe('executeC2', () => {
     expect(body.commands).toEqual(['whoami']);
   });
 });
+
+describe('getC2Tasks', () => {
+  it('GET /simulations/:id/c2/tasks returns tasks list', async () => {
+    mock.onGet('/simulations/7/c2/tasks').reply(200, {
+      tasks: [
+        {
+          id: 1,
+          mythic_task_display_id: 10,
+          callback_display_id: 1,
+          command: 'whoami',
+          params: null,
+          status: 'completed',
+          completed: true,
+          output: 'NT AUTHORITY\\SYSTEM',
+          mapping_applied: true,
+          created_at: '2026-06-10T10:00:00',
+          completed_at: '2026-06-10T10:00:05',
+        },
+      ],
+    });
+    const result = await getC2Tasks(7);
+    expect(result.tasks).toHaveLength(1);
+    expect(result.tasks[0].status).toBe('completed');
+    expect(result.tasks[0].output).toBe('NT AUTHORITY\\SYSTEM');
+    expect(mock.history['get'][0].url).toBe('/simulations/7/c2/tasks');
+  });
+});
+
+describe('listCallbackHistory', () => {
+  it('GET with page/page_size params', async () => {
+    mock.onGet('/engagements/1/c2/callbacks/2/history').reply(200, {
+      tasks: [],
+      total: 0,
+      page: 1,
+      page_size: 25,
+    });
+    const result = await listCallbackHistory(1, 2, { page: 1, pageSize: 25 });
+    expect(result.total).toBe(0);
+    const req = mock.history['get'][0];
+    expect(req.url).toBe('/engagements/1/c2/callbacks/2/history');
+    expect(req.params).toMatchObject({ page: 1, page_size: 25 });
+  });
+});
+
+describe('importC2', () => {
+  it('POST /simulations/:id/c2/import with task_display_ids', async () => {
+    mock.onPost('/simulations/7/c2/import').reply(200, { imported: 3, skipped: 1 });
+    const result = await importC2(7, {
+      callback_display_id: 2,
+      task_display_ids: [10, 11, 12, 13],
+    });
+    expect(result.imported).toBe(3);
+    expect(result.skipped).toBe(1);
+    const req = mock.history['post'][0];
+    expect(req.url).toBe('/simulations/7/c2/import');
+    const body = JSON.parse(req.data as string);
+    expect(body.callback_display_id).toBe(2);
+    expect(body.task_display_ids).toEqual([10, 11, 12, 13]);
+  });
+});