feat: org-scoped prescriptions backend, wire prescriptions page

Add the prescriptions table, validation, service and CRUD routes
(/api/prescriptions, RBAC-gated; prescriber defaults to the signed-in
clinician, prescribedAt to today) and the frontend data module. The page
now loads/persists real data and computes its status KPIs.

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

backend/src/db/schema/index.ts

@@ -2,3 +2,4 @@ export * from "./auth.js";
 export * from "./patients.js";
 export * from "./notes.js";
 export * from "./appointments.js";
+export * from "./prescriptions.js";

backend/src/db/schema/prescriptions.ts

@@ -0,0 +1,44 @@
+import {
+  date,
+  index,
+  pgTable,
+  text,
+  timestamp,
+  uuid,
+} from "drizzle-orm/pg-core";
+
+import type { PrescriptionStatus } from "../../types/prescription.js";
+import { organization, user } from "./auth.js";
+
+// One row per prescribed medication, scoped to a clinic (organization). Patient
+// identity is denormalized (name/initials/file number) so the ledger renders
+// without joining. `prescribedAt` defaults to today.
+export const prescriptions = pgTable(
+  "prescriptions",
+  {
+    id: uuid("id").primaryKey().defaultRandom(),
+    organizationId: text("organization_id")
+      .notNull()
+      .references(() => organization.id, { onDelete: "cascade" }),
+    patientFileNumber: text("patient_file_number").notNull().default(""),
+    patientName: text("patient_name").notNull(),
+    patientInitials: text("patient_initials").notNull(),
+    medication: text("medication").notNull(),
+    dose: text("dose").notNull().default(""),
+    frequency: text("frequency").notNull(),
+    prescriber: text("prescriber").notNull(),
+    prescribedAt: date("prescribed_at").defaultNow().notNull(),
+    status: text("status").$type<PrescriptionStatus>().notNull(),
+    duration: text("duration"),
+    notes: text("notes"),
+    createdBy: text("created_by").references(() => user.id, {
+      onDelete: "set null",
+    }),
+    createdAt: timestamp("created_at").defaultNow().notNull(),
+    updatedAt: timestamp("updated_at")
+      .defaultNow()
+      .$onUpdate(() => new Date())
+      .notNull(),
+  },
+  (t) => [index("prescriptions_org_idx").on(t.organizationId)],
+);