feat(structure): Use unified Email class

readme.hints.md

@@ -499,6 +499,41 @@ public getSmtpClient(host: string, port: number = 25): SmtpClient {
 - This provides access to SMTP clients, DKIM signing, and other shared functionality
 - Example: `new EmailSendJob(emailServerRef, email, options)`
 
+## Email Class Standardization (2025-05-27) - COMPLETED
+
+### Overview
+The entire codebase has been standardized to use the `Email` class as the single data structure for email handling. All Smartmail usage has been eliminated.
+
+### Key Changes
+1. **Email Class Enhanced** - Added compatibility methods: `getSubject()`, `getBody(isHtml)`, `getFrom()`
+2. **BounceManager** - Now accepts `Email` objects directly
+3. **TemplateManager** - Returns `Email` objects instead of Smartmail
+4. **EmailService** - `sendEmail()` accepts `Email` objects
+5. **RuleManager** - Uses `SmartRule<Email>` instead of `SmartRule<Smartmail>`
+6. **ApiManager** - Creates `Email` objects for API requests
+
+### Benefits
+- No more Email ↔ Smartmail conversions
+- Consistent API throughout (`email.subject` not `smartmail.options.subject`)
+- Better performance (no conversion overhead)
+- Simpler, more maintainable code
+
+### Usage Pattern
+```typescript
+// Create email
+const email = new Email({
+  from: 'sender@example.com',
+  to: 'recipient@example.com',
+  subject: 'Hello',
+  text: 'World'
+});
+
+// Pass directly through system
+await bounceManager.processBounceEmail(email);
+await templateManager.prepareEmail(templateId, context);
+await emailService.sendEmail(email);
+```
+
 ## Email Class Design Pattern (2025-05-27)
 
 ### Three-Interface Pattern for Email