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/pino-pretty/lib/utils/is-valid-date.test.js

@@ -0,0 +1,16 @@
+'use strict'
+
+process.env.TZ = 'UTC'
+
+const tap = require('tap')
+const isValidDate = require('./is-valid-date')
+
+tap.test('returns true for valid dates', async t => {
+  t.same(isValidDate(new Date()), true)
+})
+
+tap.test('returns false for non-dates and invalid dates', async t => {
+  t.plan(2)
+  t.same(isValidDate('20210621'), false)
+  t.same(isValidDate(new Date('2021-41-99')), false)
+})