feat(API-11): Route API calls through AgilitonAPI gateway

Add gateway-first pattern: when AGILITON_API_KEY is set, route all
external API calls through the gateway with X-API-Key auth. Falls back
to direct API access when gateway is unavailable.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

node_modules/es-object-atoms/RequireObjectCoercible.js

@@ -0,0 +1,11 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+
+/** @type {import('./RequireObjectCoercible')} */
+module.exports = function RequireObjectCoercible(value) {
+	if (value == null) {
+		throw new $TypeError((arguments.length > 0 && arguments[1]) || ('Cannot call method on ' + value));
+	}
+	return value;
+};