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/fastq/example.mjs

@@ -0,0 +1,9 @@
+import { promise as queueAsPromised } from './queue.js'
+
+const queue = queueAsPromised(worker, 1)
+
+console.log('the result is', await queue.push(42))
+
+async function worker (arg) {
+  return 42 * 2
+}