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/shared/ipc-channels.ts

@@ -0,0 +1,24 @@
+/**
+ * IPC Channel definitions
+ * Centralized channel names for main-renderer communication
+ */
+
+export const IPC_CHANNELS = {
+  // File operations
+  FILE_READ: 'file:read',
+  FILE_WRITE: 'file:write',
+  FILE_EXISTS: 'file:exists',
+  FILE_LIST: 'file:list',
+
+  // Extractor service
+  EXTRACTOR_RUN: 'extractor:run',
+
+  // Cleaner service
+  CLEANER_RUN: 'cleaner:run',
+
+  // Database service - MySQL
+  DATABASE_MYSQL_CONNECT: 'database:mysql:connect',
+  DATABASE_MYSQL_DISCONNECT: 'database:mysql:disconnect',
+  DATABASE_MYSQL_IS_CONNECTED: 'database:mysql:isConnected',
+  DATABASE_MYSQL_QUERY: 'database:mysql:query'
+} as const