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/is-stream/index.d.ts

@@ -0,0 +1,81 @@
+import {
+	Stream,
+	Writable as WritableStream,
+	Readable as ReadableStream,
+	Duplex as DuplexStream,
+	Transform as TransformStream,
+} from 'node:stream';
+
+/**
+@returns Whether `stream` is a [`Stream`](https://nodejs.org/api/stream.html#stream_stream).
+
+@example
+```
+import fs from 'node:fs';
+import {isStream} from 'is-stream';
+
+isStream(fs.createReadStream('unicorn.png'));
+//=> true
+
+isStream({});
+//=> false
+```
+*/
+export function isStream(stream: unknown): stream is Stream;
+
+/**
+@returns Whether `stream` is a [`stream.Writable`](https://nodejs.org/api/stream.html#stream_class_stream_writable).
+
+@example
+```
+import fs from 'node:fs';
+import {isWritableStream} from 'is-stream';
+
+isWritableStream(fs.createWriteStrem('unicorn.txt'));
+//=> true
+```
+*/
+export function isWritableStream(stream: unknown): stream is WritableStream;
+
+/**
+@returns Whether `stream` is a [`stream.Readable`](https://nodejs.org/api/stream.html#stream_class_stream_readable).
+
+@example
+```
+import fs from 'node:fs';
+import {isReadableStream} from 'is-stream';
+
+isReadableStream(fs.createReadStream('unicorn.png'));
+//=> true
+```
+*/
+export function isReadableStream(stream: unknown): stream is ReadableStream;
+
+/**
+@returns Whether `stream` is a [`stream.Duplex`](https://nodejs.org/api/stream.html#stream_class_stream_duplex).
+
+@example
+```
+import {Duplex as DuplexStream} from 'node:stream';
+import {isDuplexStream} from 'is-stream';
+
+isDuplexStream(new DuplexStream());
+//=> true
+```
+*/
+export function isDuplexStream(stream: unknown): stream is DuplexStream;
+
+/**
+@returns Whether `stream` is a [`stream.Transform`](https://nodejs.org/api/stream.html#stream_class_stream_transform).
+
+@example
+```
+import fs from 'node:fs';
+import StringifyStream from 'streaming-json-stringify';
+import {isTransformStream} from 'is-stream';
+
+isTransformStream(StringifyStream());
+//=> true
+```
+*/
+export function isTransformStream(stream: unknown): stream is TransformStream;