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/eslint/messages/shared.js

@@ -0,0 +1,18 @@
+/**
+ * @fileoverview Shared utilities for error messages.
+ * @author Josh Goldberg
+ */
+
+"use strict";
+
+/**
+ * Converts a value to a string that may be printed in errors.
+ * @param {any} value The invalid value.
+ * @param {number} indentation How many spaces to indent
+ * @returns {string} The value, stringified.
+ */
+function stringifyValueForError(value, indentation) {
+    return value ? JSON.stringify(value, null, 4).replace(/\n/gu, `\n${" ".repeat(indentation)}`) : `${value}`;
+}
+
+module.exports = { stringifyValueForError };