feat: AI chat system with LangGraph, multi-step patient flows, and appointment rescheduling

- Add floating chat window Hand-off to AI toggle (per-patient) and after-hours AI toggle (global)
- Add LangGraph-powered appointment reminder flow: AI introduces itself, classifies YES/NO, handles confirmation with appointment date/time
- Add multi-step rescheduling flow: ASAP vs next week, tomorrow offer, Mon/Tue/Wed picker, morning/afternoon time slot — automatically updates appointment in DB
- Add new patient / after-hours flow: new vs existing patient, dental insurance check, MassHealth Selenium eligibility check (auto-uses saved member ID + DOB for existing patients), self-pay fallback
- Add AI Chat Settings page (Settings → Advanced) with editable greeting templates and LangGraph flow diagrams for both reminder and new-patient flows
- Add Schedule a New Patient template option in chat window, starts new-patient conversation flow
- Add GET/PUT endpoints for AI handoff, after-hours handoff, and AI chat templates
- Add multilingual support (7 languages) across all AI reply nodes with LLM generation and hardcoded fallbacks
- Add pending reschedule in-memory store and conversation stage tracking across all flows

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

packages/db/shared/schemas/variants/pure/InsuranceContact.pure.ts

@@ -0,0 +1,12 @@
+import * as z from 'zod';
+// prettier-ignore
+export const InsuranceContactModelSchema = z.object({
+    id: z.number().int(),
+    userId: z.number().int(),
+    name: z.string(),
+    phoneNumber: z.string().nullable(),
+    createdAt: z.date(),
+    user: z.unknown()
+}).strict();
+
+export type InsuranceContactPureType = z.infer<typeof InsuranceContactModelSchema>;

packages/db/shared/schemas/variants/pure/OfficeContact.pure.ts

@@ -3,6 +3,7 @@ import * as z from 'zod';
 export const OfficeContactModelSchema = z.object({
     id: z.number().int(),
     userId: z.number().int(),
+    officeName: z.string().nullable(),
     receptionistName: z.string().nullable(),
     dentistName: z.string().nullable(),
     phoneNumber: z.string().nullable(),

packages/db/shared/schemas/variants/pure/Patient.pure.ts

@@ -18,6 +18,7 @@ export const PatientModelSchema = z.object({
     policyHolder: z.string().nullable(),
     allergies: z.string().nullable(),
     medicalConditions: z.string().nullable(),
+    preferredLanguage: z.string().nullable(),
     status: PatientStatusSchema,
     userId: z.number().int(),
     createdAt: z.date(),

packages/db/shared/schemas/variants/pure/User.pure.ts

@@ -23,7 +23,8 @@ export const UserModelSchema = z.object({
     aiSettings: z.unknown().nullable(),
     officeHours: z.unknown().nullable(),
     officeContact: z.unknown().nullable(),
-    procedureTimeslot: z.unknown().nullable()
+    procedureTimeslot: z.unknown().nullable(),
+    insuranceContacts: z.array(z.unknown())
 }).strict();
 
 export type UserPureType = z.infer<typeof UserModelSchema>;

packages/db/shared/schemas/variants/pure/index.ts

@@ -31,4 +31,5 @@ export { TwilioSettingsModelSchema } from './TwilioSettings.pure';
 export { AiSettingsModelSchema } from './AiSettings.pure';
 export { OfficeHoursModelSchema } from './OfficeHours.pure';
 export { OfficeContactModelSchema } from './OfficeContact.pure';
+export { InsuranceContactModelSchema } from './InsuranceContact.pure';
 export { ProcedureTimeslotModelSchema } from './ProcedureTimeslot.pure';