feat(admin): 新增尾首概率分析弹窗

在history页面工具栏添加"尾首概率"按钮，弹窗显示：
- 下一期尾数与前一期尾数相同的概率
- 下一期首位与前一期首位相同的概率
支持切换统计期数（30/50/100/200期）

application/admin/controller/History.php

@@ -22,7 +22,7 @@ class History extends Backend
      * 无需额外权限检查的方法（但仍在 admin 模块内，需要 admin 登录）
      * @var array
      */
-    protected $noNeedRight = ['missingNum', 'trendData', 'hotColdNumbers', 'colorWaveAnalysis', 'zodiacAnalysis', 'oddEvenAnalysis', 'bigSmallAnalysis', 'specialTrend', 'consecutiveNumbers', 'tailNumbers', 'dashboard', 'specialHeatmap', 'specialHotColdAction', 'zoneTransition', 'colorWaveTransition', 'zoneToColorTransition', 'zodiacTransition', 'tailNumberTransition', 'headNumberTransition', 'predict', 'predictV2', 'predictV3', 'optimizeWeights', 'predictByNormalRelation'];
+    protected $noNeedRight = ['missingNum', 'trendData', 'hotColdNumbers', 'colorWaveAnalysis', 'zodiacAnalysis', 'oddEvenAnalysis', 'bigSmallAnalysis', 'specialTrend', 'consecutiveNumbers', 'tailNumbers', 'dashboard', 'specialHeatmap', 'specialHotColdAction', 'zoneTransition', 'colorWaveTransition', 'zoneToColorTransition', 'zodiacTransition', 'tailNumberTransition', 'headNumberTransition', 'tailHeadProb', 'predict', 'predictV2', 'predictV3', 'optimizeWeights', 'predictByNormalRelation'];
 
     public function _initialize()
     {
@@ -388,6 +388,18 @@ class History extends Backend
         }
     }
 
+    /**
+     * 尾首概率分析
+     */
+    public function tailHeadProb()
+    {
+        if ($this->request->isAjax()) {
+            $periods = $this->request->get('periods', 100, 'intval');
+            $result = $this->model->getTailHeadProbability($periods);
+            $this->success('查询成功', null, $result);
+        }
+    }
+
     /**
      * 综合预测号码
      * 基于历史多维度转移概率分析，给出号码预测建议

application/admin/model/History.php

@@ -984,6 +984,60 @@ class History extends Model
         ];
     }
 
+    /**
+     * 尾首概率：下一期尾数/首位与前一期相同的概率
+     * 统计相邻两期特码的尾数（num%10）和首位（floor(num/10））变化
+     * @param int $periods 查询最近多少期
+     * @return array {tailProb: float, headProb: float, totalTransitions: int, periodCount: int}
+     */
+    public function getTailHeadProbability($periods = 100)
+    {
+        $history = $this
+            ->field('expect,num7,openTime')
+            ->order('openTime', 'desc')
+            ->limit($periods)
+            ->select();
+
+        if (empty($history) || count($history) < 2) {
+            return ['tailProb' => 0, 'headProb' => 0, 'totalTransitions' => 0, 'periodCount' => 0];
+        }
+
+        // 按时间升序排列（旧→新）
+        $history = array_reverse($history);
+
+        $tailSame = 0;
+        $headSame = 0;
+        $totalTransitions = 0;
+
+        for ($i = 0; $i < count($history) - 1; $i++) {
+            $currentNum = (int)$history[$i]['num7'];
+            $nextNum = (int)$history[$i + 1]['num7'];
+
+            if ($currentNum < 1 || $currentNum > 49 || $nextNum < 1 || $nextNum > 49) {
+                continue;
+            }
+
+            $totalTransitions++;
+
+            // 尾数相同（个位相同）
+            if (($currentNum % 10) === ($nextNum % 10)) {
+                $tailSame++;
+            }
+
+            // 首位相同（十位相同）
+            if (intval(floor($currentNum / 10)) === intval(floor($nextNum / 10))) {
+                $headSame++;
+            }
+        }
+
+        return [
+            'tailProb' => $totalTransitions > 0 ? round($tailSame / $totalTransitions * 100, 2) : 0,
+            'headProb' => $totalTransitions > 0 ? round($headSame / $totalTransitions * 100, 2) : 0,
+            'totalTransitions' => $totalTransitions,
+            'periodCount' => count($history)
+        ];
+    }
+
     /**
      * 区域→区域转移矩阵，单元格内显示波色概率
      * 统计上一期特码所在区域后，下一期特码在各区域的分布，以及每个区域内的波色占比

application/admin/view/history/index.html

@@ -21,6 +21,7 @@
                         <a href="javascript:;" class="btn btn-primary btn-numberfilter" title="筛号器"><i class="fa fa-filter"></i> 筛号器</a>
                         <a href="javascript:;" class="btn btn-success btn-predict" title="智能预测"><i class="fa fa-magic"></i> 智能预测</a>
 <a href="javascript:;" class="btn btn-info btn-normal-relation" title="正码关联预测"><i class="fa fa-link"></i> 正码关联预测</a>
+<a href="javascript:;" class="btn btn-warning btn-tailheadprob" title="尾首概率"><i class="fa fa-percent"></i> 尾首概率</a>
 <!--                        <a href="javascript:;" class="btn btn-success btn-dashboard" title="{:__('Dashboard')}"><i class="fa fa-tachometer"></i> {:__('Dashboard')}</a>-->
 <!--                        <a href="javascript:;" class="btn btn-success btn-add {:$auth->check('history/add')?'':'hide'}" title="{:__('Add')}" ><i class="fa fa-plus"></i> {:__('Add')}</a>-->
                     </div>