Build an Email Notification Service

Problem/Feature Description

Build a Python FastAPI service that sends transactional emails through SendGrid and logs notification history to a SQLite database.

Endpoints:

• POST /api/notifications/send -- send an email notification (to, subject, body, template_id)
• GET /api/notifications -- list sent notifications with pagination
• GET /api/notifications/{id} -- get notification details and delivery status
• POST /api/notifications/bulk -- send the same notification to multiple recipients

Business rules:

• Email addresses must be valid format
• Subject line is required, max 200 characters
• Template ID is optional -- if provided, the body is ignored and the template is used
• Bulk send is limited to 100 recipients per request
• All send attempts must be logged with timestamp and delivery status

Use sendgrid for email delivery and sqlite3/aiosqlite for the database.

Output Specification

Produce:

• app/main.py -- FastAPI application entry point
• app/routes/notifications.py -- notification route handlers
• app/db.py -- database setup and queries
• app/email_client.py -- SendGrid integration
• requirements.txt -- with dependencies listed
• .gitignore -- standard Python gitignore

You may create additional files as needed for a well-structured codebase.