refactor: complete migration from .env to YAML configuration

BREAKING CHANGE: Application now uses config.yaml instead of .env files

## Changes:
- Remove dotenv dependency from package.json
- Update all services to use ConfigManager for configuration
- Update tests to use fixed credentials instead of env vars
- Delete obsolete config-manager.test.ts (used old .env API)
- Update documentation (README.md, CLAUDE.md) to reflect new config system

## Configuration Architecture:
- ConfigManager: Centralized YAML configuration with Zod validation
- config.yaml location:
  - Development: Project root (easy to edit and version control)
  - Production: User AppData (persists across updates)
- ERP credentials: Stored in database (dbo_BIPUsers) per user
- Other settings: Stored in config.yaml (database, paths, extraction, etc.)

## Files Modified:
- package.json: Removed dotenv dependency
- cleaner-handler.ts: Use ConfigManager.getDatabaseType()
- run-migration.ts: Read from config.yaml instead of .env
- All integration tests: Use fixed test credentials
- tests/setup.ts: Removed dotenv loading
- README.md, CLAUDE.md: Updated documentation

Migration is complete. Application no longer depends on .env files.

tests/integration/mysql.test.ts

@@ -8,13 +8,13 @@ import { describe, it, expect, beforeAll, afterAll } from 'vitest'
 import { MySqlService, MySqlConfig } from '@services/database/mysql'
 
 // MySQL test configuration
-// In production, these should come from environment variables
+// For integration tests, use fixed test credentials or configure via config.yaml
 const testConfig: MySqlConfig = {
-  host: process.env.MYSQL_HOST || 'localhost',
-  port: parseInt(process.env.MYSQL_PORT || '3306'),
-  user: process.env.MYSQL_USER || 'root',
-  password: process.env.MYSQL_PASSWORD || 'password',
-  database: process.env.MYSQL_DATABASE || 'test_db'
+  host: 'localhost',
+  port: 3306,
+  user: 'root',
+  password: 'password',
+  database: 'test_db'
 }
 
 describe('MySqlService Integration Tests', () => {