dev-api: add developer portal, OpenAPI spec, and Flatenbadet case study

- New /developers/ page with API docs, SDKs, pricing, use cases
- OpenAPI 3.0 spec for Orders, Missions, Photos, Analytics
- Case study: Glasskiosken i Flatenbadet — complete ROI analysis
- Updated /order/ with recurring missions and frequency dropdown

services/frilans-payout/node_modules/execa/lib/promise.js

@@ -0,0 +1,36 @@
+// eslint-disable-next-line unicorn/prefer-top-level-await
+const nativePromisePrototype = (async () => {})().constructor.prototype;
+
+const descriptors = ['then', 'catch', 'finally'].map(property => [
+	property,
+	Reflect.getOwnPropertyDescriptor(nativePromisePrototype, property),
+]);
+
+// The return value is a mixin of `childProcess` and `Promise`
+export const mergePromise = (spawned, promise) => {
+	for (const [property, descriptor] of descriptors) {
+		// Starting the main `promise` is deferred to avoid consuming streams
+		const value = typeof promise === 'function'
+			? (...args) => Reflect.apply(descriptor.value, promise(), args)
+			: descriptor.value.bind(promise);
+
+		Reflect.defineProperty(spawned, property, {...descriptor, value});
+	}
+};
+
+// Use promises instead of `child_process` events
+export const getSpawnedPromise = spawned => new Promise((resolve, reject) => {
+	spawned.on('exit', (exitCode, signal) => {
+		resolve({exitCode, signal});
+	});
+
+	spawned.on('error', error => {
+		reject(error);
+	});
+
+	if (spawned.stdin) {
+		spawned.stdin.on('error', error => {
+			reject(error);
+		});
+	}
+});