chore(01-01): add FERNET_KEY config and email tables migration

- Add FERNET_KEY to .env.example with generation instructions
- Register email.models in aerich_config.py and app.py
- Register email blueprint in app.py
- Create database migration for email_accounts, email_sync_status, emails
- Migration includes proper foreign keys and indexes

.env.example

@@ -54,3 +54,14 @@ OIDC_USE_DISCOVERY=true
 YNAB_ACCESS_TOKEN=your-ynab-personal-access-token
 # Optional: Specify a budget ID, or leave empty to use the default/first budget
 YNAB_BUDGET_ID=
+
+# Mealie Configuration
+# Base URL for your Mealie instance (e.g., http://192.168.1.5:9000 or https://mealie.example.com)
+MEALIE_BASE_URL=http://192.168.1.5:9000
+# Get your API token from Mealie's user settings page
+MEALIE_API_TOKEN=your-mealie-api-token
+
+# Email Integration
+# Email Encryption Key (32-byte URL-safe base64)
+# Generate with: python -c "from cryptography.fernet import Fernet; print(Fernet.generate_key().decode())"
+FERNET_KEY=your-fernet-key-here