feat: add SQL Server support and refactor database layer for multi-database compatibility

- Add SqlServerService integration alongside existing MySQL support
- Refactor DAOs (DiscreteMaterialPlanDAO, MaterialsToBeDeletedDAO, BipUsersDAO) to support both MySQL and SQL Server
- Update validation handler to dynamically select database service based on DB_TYPE environment variable
- Add connection pooling and proper connection management for SQL Server
- Update package-lock.json dependency peer flags

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/main/services/database/sql-server.ts

@@ -98,8 +98,9 @@ export class SqlServerService {
       const result = await request.query(sqlString)
 
       // Convert recordset to array of objects
-      const columns = result.recordset.columns?.map((col) => col.name) || []
       const rows = result.recordset as Record<string, unknown>[]
+      // Extract column names from the first row if available
+      const columns = rows.length > 0 ? Object.keys(rows[0]) : []
 
       return {
         rows,
@@ -137,8 +138,9 @@ export class SqlServerService {
       const result = await request.query(sqlString)
 
       // Convert recordset to array of objects
-      const columns = result.recordset.columns?.map((col) => col.name) || []
       const rows = result.recordset as Record<string, unknown>[]
+      // Extract column names from the first row if available
+      const columns = rows.length > 0 ? Object.keys(rows[0]) : []
 
       return {
         rows,