feat: enhance new-patient AI chat flow with full scheduling and eligibility

- Add 3-message intro (self-intro → empathetic ack → new/existing question) via single TwiML response to guarantee delivery order
- Detect reschedule intent from first message; look up existing appointment date
- New patient flow: ask insurance type → MassHealth consent → member ID + DOB → Selenium eligibility check
- Post-eligibility: active → ask appointment date/time with office-hours validation; inactive → ask other insurance or collect contact info
- Date/time collection mirrors reschedule flow: check office day open, ask time, validate against office hours
- Auto-create appointment in schedule for known patients on confirmation; use first available staff member
- Add openPhoneReply toggle (Settings → AI Chat) to respond to any number at any time
- Add 5-minute inactivity timeout: reset conversation to initial stage and clear pending state
- Normalize MassHealth DOB to zero-padded MM/DD/YYYY before Selenium submission
- Expand isExistingPatient classifier to recognize "old patient", "old", "previous", "prior"
- Existing patient confirmation message now acknowledges patient type before asking about insurance

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/db/generated/prisma/index-browser.js

@@ -423,7 +423,8 @@ exports.Prisma.AiSettingsScalarFieldEnum = {
   id: 'id',
   userId: 'userId',
   apiKey: 'apiKey',
-  afterHoursEnabled: 'afterHoursEnabled'
+  afterHoursEnabled: 'afterHoursEnabled',
+  openPhoneReply: 'openPhoneReply'
 };
 
 exports.Prisma.OfficeHoursScalarFieldEnum = {