I need to connect our custom-built PHP CRM to Gmail so that every message—across all email folders—syncs seamlessly into our system. Incoming emails should be stored against the relevant contact, and I want to be able to compose, send, and reply directly from the CRM interface. Key requirements • Use the official Gmail API with OAuth 2.0 so users can grant access securely. • Pull full message content, attachments, and metadata while capturing read, unread, replied, and forwarded statuses. • Write clean PHP code that fits our existing MVC structure and respects current database schemas. • Maintain two-way sync: actions taken in Gmail (read, delete, label) should reflect in the CRM, and vice versa. • Provide clear setup instructions plus a brief walkthrough of any new tables, endpoints, or cron jobs. A short demo on our staging server will complete the job, after which I’ll test the flow end-to-end before sign-off.