feat(mssql): add MSSQL writer for generating DDL from database schema

- Implement MSSQL writer to generate SQL scripts for creating schemas, tables, and constraints.
- Support for identity columns, indexes, and extended properties.
- Add tests for column definitions, table creation, primary keys, foreign keys, and comments.
- Include testing guide and sample schema for integration tests.

docker-compose.yml

@@ -1,6 +1,21 @@
 version: '3.8'
 
 services:
+  mssql:
+    image: mcr.microsoft.com/mssql/server:2022-latest
+    environment:
+      - ACCEPT_EULA=Y
+      - SA_PASSWORD=StrongPassword123!
+      - MSSQL_PID=Express
+    ports:
+      - "1433:1433"
+    volumes:
+      - ./test_data/mssql/test_schema.sql:/test_schema.sql
+    healthcheck:
+      test: ["CMD", "/opt/mssql-tools/bin/sqlcmd", "-S", "localhost", "-U", "sa", "-P", "StrongPassword123!", "-Q", "SELECT 1"]
+      interval: 5s
+      timeout: 3s
+      retries: 10
   postgres:
     image: postgres:16-alpine
     container_name: relspec-test-postgres