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>

backend/src/db/schema/appointments.ts

@@ -22,6 +22,9 @@ export const appointments = pgTable(
     type: text("type").notNull(),
     provider: text("provider").notNull(),
     status: text("status").$type<AppointmentStatus>().notNull(),
+    // Provenance: "ai" rows were drafted by the chat agent (possibly with
+    // placeholder fields) and are flagged for clinician review/edit.
+    source: text("source").$type<"manual" | "ai">().notNull().default("manual"),
     createdBy: text("created_by").references(() => user.id, {
       onDelete: "set null",
     }),

backend/src/db/schema/patients.ts

@@ -50,6 +50,10 @@ export const patients = pgTable(
     primaryProviderId: text("primary_provider_id").references(() => user.id, {
       onDelete: "set null",
     }),
+    // Provenance: "ai" rows were imported/drafted by the chat agent (possibly
+    // with auto-generated file numbers or placeholder fields) and are flagged
+    // for clinician review/edit.
+    source: text("source").$type<"manual" | "ai">().notNull().default("manual"),
     createdBy: text("created_by").references(() => user.id, {
       onDelete: "set null",
     }),

backend/src/db/schema/prescriptions.ts

@@ -31,6 +31,8 @@ export const prescriptions = pgTable(
     status: text("status").$type<PrescriptionStatus>().notNull(),
     duration: text("duration"),
     notes: text("notes"),
+    // Provenance: "ai" rows were drafted by the chat agent and flagged for review.
+    source: text("source").$type<"manual" | "ai">().notNull().default("manual"),
     createdBy: text("created_by").references(() => user.id, {
       onDelete: "set null",
     }),