feat: 运营报告生成功能

- 后端新增 /admin/stats/report 接口，生成14天运营数据报告
- 报告内容：垃圾信息变化趋势、高频风险词Top10、误判率趋势
- 前端运营看板增加"生成报告"按钮，展示完整报告
- 支持复制报告文本到剪贴板

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

miniprogram/pages/admin-dashboard/index.js

@@ -7,7 +7,9 @@ Page({
     kpis: [],
     bars: [],
     sourceDist: [],
-    topKeywords: []
+    topKeywords: [],
+    report: null,
+    reportLoading: false
   },
 
   formatPercent(value, digits = 2) {
@@ -67,5 +69,74 @@ Page({
       this.setData({ loading: false })
       if (fromPullDown) wx.stopPullDownRefresh()
     }
+  },
+
+  async generateReport() {
+    this.setData({ reportLoading: true })
+    try {
+      const report = await request({ url: '/admin/stats/report' })
+
+      // 处理趋势数据，计算进度条宽度
+      const spamTrend = (report.spam_trend || []).map((item) => {
+        const maxBlocked = Math.max(...(report.spam_trend || []).map((r) => r.blocked || 0), 1)
+        return {
+          ...item,
+          blocked_percent: `${Math.max(4, Math.round((item.blocked || 0) / maxBlocked * 100))}%`
+        }
+      })
+
+      const misjudgeTrend = (report.misjudge_trend || []).map((item) => ({
+        ...item,
+        rate_percent: `${Math.round((item.misjudge_rate || 0) * 100)}%`
+      }))
+
+      this.setData({
+        report: {
+          ...report,
+          spam_trend: spamTrend,
+          misjudge_trend: misjudgeTrend
+        }
+      })
+
+      wx.showToast({ title: '报告已生成', icon: 'success' })
+    } finally {
+      this.setData({ reportLoading: false })
+    }
+  },
+
+  closeReport() {
+    this.setData({ report: null })
+  },
+
+  copyReportText() {
+    const report = this.data.report
+    if (!report) return
+
+    const summary = report.summary || {}
+    const lines = [
+      `【垃圾信息运营报告】`,
+      `报告周期：${report.period}`,
+      `生成时间：${(report.report_date || '').replace('T', ' ').slice(0, 19)}`,
+      '',
+      `【汇总统计】`,
+      `总发布量：${summary.total_posts || 0} 条`,
+      `拦截量：${summary.total_blocked || 0} 条`,
+      `正常发布：${summary.total_published || 0} 条`,
+      `拦截率：${this.formatPercent(summary.blocked_ratio, 2)}`,
+      `复核总数：${summary.total_reviews || 0} 次`,
+      `误判放行：${summary.total_approved || 0} 次`,
+      `平均误判率：${summary.avg_misjudge_rate_text || '0%'}`,
+      '',
+      `【高频风险词 Top10】`,
+      (report.top_keywords || []).slice(0, 10).map((k) => `${k.token}(${k.count}次)`).join('、'),
+      '',
+      `【近7日趋势】`,
+      (report.spam_trend || []).slice(-7).map((t) => `${t.label}: 拦截${t.blocked}条，发布${t.published}条`).join('\n')
+    ]
+
+    wx.setClipboardData({
+      data: lines.join('\n'),
+      success: () => wx.showToast({ title: '报告已复制', icon: 'success' })
+    })
   }
 })