feat: add AI recall calling — books existing patients for routine cleanings

Adds a new recall conversation flow (recall-graph.ts) triggered from the
Patient Connection "AI Call" button: offers an existing patient a routine
exam & cleaning, classifies their yes/no reply, then books directly onto
the schedule (Column A, 30-minute slots, real conflict checking against
office hours and existing appointments) instead of only capturing a
preference for staff to follow up on.

Also adds a "Voice call" label in the message thread to distinguish call
transcripts from SMS, and updates the Call Templates settings UI with an
editable recall greeting.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/Backend/src/ai/aiHandoffStore.ts

@@ -3,6 +3,9 @@ import { prisma as db } from "@repo/db/client";
 export type ConversationStage =
   | "initial"
   | "reminder_initial"
+  | "recall_initial"
+  | "recall_asked_datetime"
+  | "recall_asked_time_for_date"
   | "greeted"
   | "done"
   | "new_patient_greeted"
@@ -81,6 +84,12 @@ export async function startRescheduleConversation(userId: number, patientId: num
   await setStage(userId, patientId, "asked_reschedule_confirm");
 }
 
+// Recall: office proactively calls/texts an existing patient to offer a
+// routine exam & cleaning (typically covered at no cost by insurance).
+export async function startRecallConversation(userId: number, patientId: number): Promise<void> {
+  await setStage(userId, patientId, "recall_initial");
+}
+
 // ── Pending reschedule (in-memory — seconds-lived within a single exchange) ───
 
 interface PendingReschedule {