新增 SQL 题型：SQLite 内联判题（不依赖外部沙箱）

- SQL 作为语言接入现有提交流程，judge_task 按 language 分流到 SQLJudgeDispatcher
- judge/sql_runner.py：内存 SQLite 判题核心，查询题比结果集/增删改题比表状态，
  authorizer + progress_handler + max_page_count 三重防护
- dispatcher 提取 _process_judge_result/_push_status 供 SQL 判题复用（行为不变）
- 测试点通道支持 1.sql..N.sql 压缩包，出题只需数据脚本+标准答案
- Problem 增加 sql_config 字段；options 数据迁移注册 SQL 语言

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

problem/migrations/0011_problem_sql_config.py

@@ -0,0 +1,18 @@
+# Generated by Django 6.0.4 on 2026-07-02 15:57
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('problem', '0010_problem_ast_rules'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='problem',
+            name='sql_config',
+            field=models.JSONField(blank=True, default=None, null=True),
+        ),
+    ]