feat: improve OpenAPI request contracts and examples (#418)

* feat: improve OpenAPI request contracts and examples

* fix: align AJV docs plugin typing

* fix: preserve runtime behavior for OpenAPI schemas

* fix: align medication OpenAPI body schema with app payloads

backend/src/test/stock-semantics-parity.test.ts

@@ -4,6 +4,7 @@ import { migrate } from "drizzle-orm/libsql/migrator";
 import Fastify, { type FastifyInstance } from "fastify";
 import { afterAll, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
 import { runAlterMigrations } from "../db/db-utils.js";
+import { documentationSchemaAjv } from "../utils/documentation-schema-keywords.js";
 
 const { testClient, testDb, mockedEnv } = vi.hoisted(() => {
 	const { createClient } = require("@libsql/client");
@@ -173,7 +174,7 @@ describe("Stock semantics parity (planner usage vs scheduler)", () => {
 	beforeAll(async () => {
 		await migrate(testDb, { migrationsFolder });
 		await runAlterMigrations(testClient);
-		app = Fastify({ logger: false });
+		app = Fastify({ logger: false, ajv: documentationSchemaAjv });
 		await app.register(medicationRoutes);
 		await app.ready();
 	});