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/zod/mini/package.json

@@ -0,0 +1,6 @@
+{ 
+  "type": "module",
+  "main": "./index.cjs",
+  "module": "./index.js",
+  "types": "./index.d.cts" 
+}