feat: implement IPC handlers, database services and Extractor UI

- Add SqlServerService and MySqlService for database persistence
- Implement IPC handlers for file, extractor, cleaner, and database operations
- Define IPC API types and update preload script
- Create ExtractorPage UI with OrderNumberInput component
- Add unit and integration tests for MySQL and SQL Server
- Update vitest config with path aliases

src/main/services/database/mysql.ts

@@ -0,0 +1,123 @@
+import mysql from 'mysql2/promise'
+
+export interface MySqlConfig {
+  host: string
+  port: number
+  user: string
+  password: string
+  database: string
+}
+
+export interface MySqlQueryResult {
+  rows: Record<string, unknown>[]
+  columns: string[]
+  rowCount: number
+}
+
+export class MySqlService {
+  private connection: mysql.Connection | null = null
+  private config: MySqlConfig
+
+  constructor(config: MySqlConfig) {
+    this.config = config
+  }
+
+  /**
+   * Connect to MySQL database
+   */
+  async connect(): Promise<void> {
+    if (this.connection) {
+      throw new Error('Already connected to MySQL')
+    }
+
+    try {
+      this.connection = await mysql.createConnection({
+        host: this.config.host,
+        port: this.config.port,
+        user: this.config.user,
+        password: this.config.password,
+        database: this.config.database
+      })
+
+      // Test connection
+      await this.connection.ping()
+    } catch (error) {
+      throw new Error(`Failed to connect to MySQL: ${(error as Error).message}`)
+    }
+  }
+
+  /**
+   * Disconnect from MySQL database
+   */
+  async disconnect(): Promise<void> {
+    if (!this.connection) {
+      return
+    }
+
+    try {
+      await this.connection.end()
+      this.connection = null
+    } catch (error) {
+      throw new Error(`Failed to disconnect from MySQL: ${(error as Error).message}`)
+    }
+  }
+
+  /**
+   * Check if connected to MySQL database
+   */
+  isConnected(): boolean {
+    return this.connection !== null
+  }
+
+  /**
+   * Execute a query and return results
+   */
+  async query(sql: string, params?: any[]): Promise<MySqlQueryResult> {
+    if (!this.connection) {
+      throw new Error('Not connected to MySQL. Call connect() first.')
+    }
+
+    try {
+      const [rows, fields] = await this.connection.execute(sql, params)
+
+      // Convert rows to plain objects and extract column names
+      const columns = fields.map((field) => field.name)
+      const rowCount = Array.isArray(rows) ? rows.length : 0
+
+      // Type assertion for rows - mysql2 returns different types based on query
+      const typedRows = Array.isArray(rows) ? (rows as Record<string, unknown>[]) : []
+
+      return {
+        rows: typedRows,
+        columns,
+        rowCount
+      }
+    } catch (error) {
+      throw new Error(`MySQL query failed: ${(error as Error).message}`)
+    }
+  }
+
+  /**
+   * Execute multiple queries in a transaction
+   */
+  async transaction(queries: { sql: string; params?: any[] }[]): Promise<void> {
+    if (!this.connection) {
+      throw new Error('Not connected to MySQL. Call connect() first.')
+    }
+
+    try {
+      await this.connection.beginTransaction()
+
+      for (const { sql, params } of queries) {
+        await this.connection.execute(sql, params)
+      }
+
+      await this.connection.commit()
+    } catch (error) {
+      if (this.connection) {
+        await this.connection.rollback()
+      }
+      throw new Error(`MySQL transaction failed: ${(error as Error).message}`)
+    }
+  }
+}