feat: add email system with multi-provider support

Implements a comprehensive email system with:
- Multi-provider support (SMTP, SendGrid, Mailgun, Amazon SES)
- Database-stored templates with i18n (EN, FR, DE, LB)
- Jinja2 template rendering with variable interpolation
- Email logging for debugging and compliance
- Debug mode for development (logs instead of sending)
- Welcome email integration in signup flow

New files:
- models/database/email.py: EmailTemplate and EmailLog models
- app/services/email_service.py: Provider abstraction and service
- scripts/seed_email_templates.py: Template seeding script
- tests/unit/services/test_email_service.py: 28 unit tests
- docs/features/email-system.md: Complete documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/core/config.py

@@ -125,6 +125,39 @@ class Settings(BaseSettings):
     stripe_webhook_secret: str = ""
     stripe_trial_days: int = 30  # 1-month free trial (card collected upfront but not charged)
 
+    # =============================================================================
+    # EMAIL CONFIGURATION
+    # =============================================================================
+    # Provider: smtp, sendgrid, mailgun, ses
+    email_provider: str = "smtp"
+    email_from_address: str = "noreply@wizamart.com"
+    email_from_name: str = "Wizamart"
+    email_reply_to: str = ""  # Optional reply-to address
+
+    # SMTP Settings (used when email_provider=smtp)
+    smtp_host: str = "localhost"
+    smtp_port: int = 587
+    smtp_user: str = ""
+    smtp_password: str = ""
+    smtp_use_tls: bool = True
+    smtp_use_ssl: bool = False  # For port 465
+
+    # SendGrid (used when email_provider=sendgrid)
+    sendgrid_api_key: str = ""
+
+    # Mailgun (used when email_provider=mailgun)
+    mailgun_api_key: str = ""
+    mailgun_domain: str = ""
+
+    # Amazon SES (used when email_provider=ses)
+    aws_access_key_id: str = ""
+    aws_secret_access_key: str = ""
+    aws_region: str = "eu-west-1"
+
+    # Email behavior
+    email_enabled: bool = True  # Set to False to disable all emails
+    email_debug: bool = False  # Log emails instead of sending (for development)
+
     # =============================================================================
     # DEMO/SEED DATA CONFIGURATION
     # =============================================================================