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/has-flag/index.d.ts

@@ -0,0 +1,39 @@
+/**
+Check if [`argv`](https://nodejs.org/docs/latest/api/process.html#process_process_argv) has a specific flag.
+
+@param flag - CLI flag to look for. The `--` prefix is optional.
+@param argv - CLI arguments. Default: `process.argv`.
+@returns Whether the flag exists.
+
+@example
+```
+// $ ts-node foo.ts -f --unicorn --foo=bar -- --rainbow
+
+// foo.ts
+import hasFlag = require('has-flag');
+
+hasFlag('unicorn');
+//=> true
+
+hasFlag('--unicorn');
+//=> true
+
+hasFlag('f');
+//=> true
+
+hasFlag('-f');
+//=> true
+
+hasFlag('foo=bar');
+//=> true
+
+hasFlag('foo');
+//=> false
+
+hasFlag('rainbow');
+//=> false
+```
+*/
+declare function hasFlag(flag: string, argv?: string[]): boolean;
+
+export = hasFlag;