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/fast-safe-stringify/index.d.ts

@@ -0,0 +1,23 @@
+declare function stringify(
+  value: any,
+  replacer?: (key: string, value: any) => any,
+  space?: string | number,
+  options?: { depthLimit: number | undefined; edgesLimit: number | undefined }
+): string;
+
+declare namespace stringify {
+  export function stable(
+    value: any,
+    replacer?: (key: string, value: any) => any,
+    space?: string | number,
+    options?: { depthLimit: number | undefined; edgesLimit: number | undefined }
+  ): string;
+  export function stableStringify(
+    value: any,
+    replacer?: (key: string, value: any) => any,
+    space?: string | number,
+    options?: { depthLimit: number | undefined; edgesLimit: number | undefined }
+  ): string;
+}
+
+export default stringify;