feat: persist AI conversation state in DB and fix LangGraph flow bugs

- Replace in-memory Maps in aiHandoffStore with DB-backed async functions
  using new patient_conversation table (stage + aiHandoff per patient)
- Add afterHoursEnabled to ai_settings table (persists across restarts)
- Fix runtime crash in reschedule-graph: mon/tue/wed variables were out
  of scope in the next-week fallback branch (ReferenceError)
- Wire rescheduleGreeting and generalFallback chat templates through to
  LangGraph nodes so user-configured messages take effect
- Add otherNode to reminder-graph to handle unclassified patient replies
  (e.g. "I want another appointment") and route to booking flow
- Fetch chatTemplates once per webhook request instead of per stage

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

packages/db/shared/schemas/objects/PatientInclude.schema.ts

@@ -8,6 +8,7 @@ import { PdfGroupFindManySchema as PdfGroupFindManySchema } from '../findManyPdf
 import { PaymentFindManySchema as PaymentFindManySchema } from '../findManyPayment.schema';
 import { CommunicationFindManySchema as CommunicationFindManySchema } from '../findManyCommunication.schema';
 import { PatientDocumentFindManySchema as PatientDocumentFindManySchema } from '../findManyPatientDocument.schema';
+import { PatientConversationArgsObjectSchema as PatientConversationArgsObjectSchema } from './PatientConversationArgs.schema';
 import { PatientCountOutputTypeArgsObjectSchema as PatientCountOutputTypeArgsObjectSchema } from './PatientCountOutputTypeArgs.schema'
 
 const makeSchema = () => z.object({
@@ -19,6 +20,7 @@ const makeSchema = () => z.object({
   payment: z.union([z.boolean(), z.lazy(() => PaymentFindManySchema)]).optional(),
   communications: z.union([z.boolean(), z.lazy(() => CommunicationFindManySchema)]).optional(),
   documents: z.union([z.boolean(), z.lazy(() => PatientDocumentFindManySchema)]).optional(),
+  conversation: z.union([z.boolean(), z.lazy(() => PatientConversationArgsObjectSchema)]).optional(),
   _count: z.union([z.boolean(), z.lazy(() => PatientCountOutputTypeArgsObjectSchema)]).optional()
 }).strict();
 export const PatientIncludeObjectSchema: z.ZodType<Prisma.PatientInclude> = makeSchema() as unknown as z.ZodType<Prisma.PatientInclude>;