feat: 更新分期方案初始化脚本，匹配最新表结构

- 更新表名和字段名为小写格式
- 修正字段类型以匹配实体类定义
- 新增缺失字段：scheme_type, down_payment_ratio等
- 添加索引优化查询性能
- 完善表和字段注释

LCXiaoguan-common/LCXiaoguan-common-doc/pom.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <groupId>org.dromara</groupId>
+        <artifactId>LCXiaoguan-common</artifactId>
+        <version>${revision}</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>LCXiaoguan-common-doc</artifactId>
+
+    <description>
+        LCXiaoguan-common-doc 系统接口
+    </description>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.dromara</groupId>
+            <artifactId>LCXiaoguan-common-core</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springdoc</groupId>
+            <artifactId>springdoc-openapi-starter-webmvc-api</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>com.github.therapi</groupId>
+            <artifactId>therapi-runtime-javadoc</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.module</groupId>
+            <artifactId>jackson-module-kotlin</artifactId>
+        </dependency>
+
+    </dependencies>
+
+</project>
+