feat(server): 后端从原型 fms-api 迁入并重整包结构

迁移：包名 cn.g3soft.fmsapi → cn.g3soft.erp；artifactId/name fms-api → erp-api；启动类 FmsApiApplication → ErpApiApplication；配置前缀 fms.* → erp.*；FMS_JWT_SECRET → ERP_JWT_SECRET；未带入流程引擎（service/workflow、WorkflowController*）、数据库迁移脚本（config/migrations、tools/migration）与 data/files；一并迁入 Maven Wrapper、config/dbconfigs、config/legacy-tls.security、start.cmd。

重构：拆解 utils.DbUtils（1470 行）为 common.util.SqlText + database.{MetadataReader,RowReader,RowWriter} + database.model（5 个 record）；认证专用账号查询移出访问层到 service.auth.UserAccountReader；新建 common/（ApiResponse + exception 6 + util 5 + util/snowflake 9）；database/ 分 org/（多机构连接）与 model/（纯数据载体）；JwtUtils 与客户端信息采集簇归入 service.auth。

清理：删除迁移带入的空目录、HELP.md，及 pom 中 Initializr 留下的空 url/licenses/developers/scm；修正 OrgDataSourceFactoryTests 的陈旧断言（停留在 2026-07 的旧策略，实现已于 2026-08 反转为继续重试、不停建连线程、不 failFast）。

验证：mvn test 80/80 通过；另有 2 个 @SpringBootTest 需真实 SQL Server。本次仅提交 server/；根 .gitignore、根 .gitattributes 与 docs/ 的同步改动不在本次范围内。

code/g3soft-erp/server/config/dbconfigs/README.md

@@ -0,0 +1,27 @@
+# Organization Database Configs
+
+Each organization uses one SQL Server connection file named `{ORG_ID}.properties`.
+Organization IDs are normalized to uppercase and may contain only letters, numbers,
+underscores, and hyphens.
+
+Example: `G3HD.properties`
+
+```properties
+url=jdbc:sqlserver://127.0.0.1:1433;databaseName=G3HD
+username=sa
+password=your-password
+driver=com.microsoft.sqlserver.jdbc.SQLServerDriver
+```
+
+The `*.properties` files in this directory are ignored by Git.
+
+## Development startup for legacy SQL Server
+
+Run the following command from the `server` directory when connecting to a
+legacy SQL Server that only supports TLS 1.0:
+
+```batch
+set JAVA_HOME=D:\devtool\jdk\jdk-21
+set PATH=%JAVA_HOME%\bin;%PATH%
+mvn "-Dspring-boot.run.jvmArguments=-Djava.security.properties=./config/legacy-tls.security" spring-boot:run
+```

code/g3soft-erp/server/config/legacy-tls.security

@@ -0,0 +1,3 @@
+# Development-only compatibility for SQL Server 2008 R2.
+# Keep this override scoped to the erp-api JVM.
+jdk.tls.disabledAlgorithms=SSLv3, TLSv1.1, DTLSv1.0, RC4, DES, MD5withRSA, DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, ECDH