RetellAI Phone Agent for Lead Qualification via Twilio

# ✅ General Workflow Explanation
##  This workflow automates outbound and inbound lead calls with RetellAI, Google Sheets, OpenAI, and Gmail. It handles:

Scheduling and reminding outbound qualification calls
Handling inbound appointment calls
Automatically updating records and sending summaries post-call

## 👉 Dependencies:

Active RetellAI API key
Google Sheet set up with lead data
Gmail API credentials configured