feat: AI-added records save with placeholders + "Added by AI" provenance

Stop blocking AI imports/proposals on missing non-critical fields. Records
the chat agent drafts now save with safe placeholders, auto-generated file
numbers, and a source="ai" marker that surfaces an "Added by AI" badge so a
clinician can review/edit them later.

Backend:
- add `source` (manual|ai) column to patients/appointments/prescriptions
  (migration 0014) + canonical types, services, validation schemas
- relax patient/appointment validation: empty file number allowed, demographic
  + type/provider/initials fall back to placeholders (initials derived from name)
- patients.generateFileNumber() auto-assigns an MRN when one is missing
- proposeAppointment accepts a name when no file number resolves; AI commits +
  /api/ai/import stamp source="ai"

Frontend:
- `source` on Appointment/Patient/Prescription types; AI commits send source="ai"
- reusable <AiBadge> shown on the Patients table/detail and prescriptions list

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/components/prescriptions/prescriptions-view.tsx

@@ -4,6 +4,7 @@ import { CircleCheck, Clock, Pill, Plus, Search } from "lucide-react";
 import { type ReactNode, useEffect, useMemo, useState } from "react";
 import { useTranslation } from "react-i18next";
 
+import { AiBadge } from "@/components/ai-badge";
 import {
   AddPrescriptionDialog,
   type NewPrescription,
@@ -93,6 +94,7 @@ function RxRow({ rx, onOpen }: { rx: Prescription; onOpen: () => void }) {
           {formatPrescribedAt(rx.prescribedAt)}
         </span>
       </div>
+      <AiBadge source={rx.source} />
       <Badge variant={statusVariant[rx.status]}>
         {t(`prescriptions.status.${rx.status}`)}
       </Badge>