fix(db): complete PostgreSQL integration in validation and cleaner services

OrderNumberResolver, validation, and cleaner services had incomplete
PostgreSQL support - they only handled SQL Server and MySQL, causing
PostgreSQL to fall through to MySQL code paths with invalid syntax
(backticks, ? placeholders) and missing schema.table name splitting.

Changes:
- Add PostgreSQL SQL generation ($N params, double-quoted identifiers)
  in OrderNumberResolver, validation-application-service,
  production-input-service, and validation-database
- Add PostgreSQL to database factory functions in validation-database
  and cleaner-application-service
- Add UPPER, LOWER, and 40+ common SQL functions to SQL_KEYWORDS to
  prevent prepareSql() from quoting them as identifiers

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main/services/validation/validation-database.ts

@@ -1,8 +1,9 @@
 import { ConfigManager } from '../config/config-manager'
 import { MySqlService } from '../database/mysql'
 import { SqlServerService } from '../database/sql-server'
+import { PostgreSqlService } from '../database/postgresql'
 
-export type ValidationDatabaseService = MySqlService | SqlServerService
+export type ValidationDatabaseService = MySqlService | SqlServerService | PostgreSqlService
 
 export async function createValidationDatabaseService(): Promise<ValidationDatabaseService> {
   const configManager = ConfigManager.getInstance()
@@ -26,6 +27,19 @@ export async function createValidationDatabaseService(): Promise<ValidationDatab
     return sqlServerService
   }
 
+  if (dbType === 'postgresql') {
+    const dbConfig = config.database.postgresql
+    const pgService = new PostgreSqlService({
+      host: dbConfig.host,
+      port: dbConfig.port,
+      user: dbConfig.username,
+      password: dbConfig.password,
+      database: dbConfig.database
+    })
+    await pgService.connect()
+    return pgService
+  }
+
   const dbConfig = config.database.mysql
   const mysqlService = new MySqlService({
     host: dbConfig.host,
@@ -42,14 +56,20 @@ export function getValidationTableName(mysqlTableName: string): string {
   const configManager = ConfigManager.getInstance()
   const dbType = configManager.getDatabaseType()
 
-  if (dbType === 'sqlserver') {
+  if (dbType === 'sqlserver' || dbType === 'postgresql') {
     const firstUnderscoreIndex = mysqlTableName.indexOf('_')
     if (firstUnderscoreIndex > 0) {
       const schema = mysqlTableName.substring(0, firstUnderscoreIndex)
       const tableName = mysqlTableName.substring(firstUnderscoreIndex + 1)
-      return `[${schema}].[${tableName}]`
+      if (dbType === 'sqlserver') {
+        return `[${schema}].[${tableName}]`
+      }
+      return `"${schema}"."${tableName}"`
     }
-    return `[dbo].[${mysqlTableName}]`
+    if (dbType === 'sqlserver') {
+      return `[dbo].[${mysqlTableName}]`
+    }
+    return `"public"."${mysqlTableName}"`
   }
 
   return mysqlTableName