feat: 增加/api/questions/pdf接口调试questions表的参数

app/Http/Controllers/Api/QuestionPdfController.php

@@ -45,7 +45,7 @@ class QuestionPdfController extends Controller
             'teacher_name' => 'nullable|string|max:50',
             'paper_name' => 'nullable|string|max:100',
             'include_grading' => 'nullable|boolean',
-            'source' => 'nullable|string|in:default,ai', // 题库来源：default=默认表(questions_tem)，ai=ai表(questions_ai)
+            'source' => 'nullable|string|in:default,ai,main', // 题库来源：default=questions_tem，ai=questions_ai，main=questions
         ]);
 
         if ($validator->fails()) {
@@ -63,7 +63,7 @@ class QuestionPdfController extends Controller
         $teacherName = $request->input('teacher_name', '');
         $paperName = $request->input('paper_name', '专项练习');
         $includeGrading = $request->input('include_grading', false);
-        $source = $request->input('source', 'default'); // 题库来源：default=questions_tem, ai=questions_ai
+        $source = $request->input('source', 'default'); // 题库来源：default=questions_tem, ai=questions_ai, main=questions
 
         Log::info('生成指定题目PDF', [
             'question_ids' => $questionIds,
@@ -74,7 +74,11 @@ class QuestionPdfController extends Controller
 
         try {
             // 1. Fetch questions from database
-            $tableName = $source === 'ai' ? 'questions_ai' : 'questions_tem';
+            $tableName = match ($source) {
+                'ai' => 'questions_ai',
+                'main' => 'questions',
+                default => 'questions_tem',
+            };
 
             $questions = DB::connection('remote_mysql')
                 ->table($tableName)