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/router/package.json

@@ -0,0 +1,44 @@
+{
+  "name": "router",
+  "description": "Simple middleware-style router",
+  "version": "2.2.0",
+  "author": "Douglas Christopher Wilson <doug@somethingdoug.com>",
+  "contributors": [
+    "Blake Embrey <hello@blakeembrey.com>"
+  ],
+  "license": "MIT",
+  "repository": "pillarjs/router",
+  "dependencies": {
+    "debug": "^4.4.0",
+    "depd": "^2.0.0",
+    "is-promise": "^4.0.0",
+    "parseurl": "^1.3.3",
+    "path-to-regexp": "^8.0.0"
+  },
+  "devDependencies": {
+    "finalhandler": "^2.1.0",
+    "mocha": "10.2.0",
+    "nyc": "15.1.0",
+    "run-series": "^1.1.9",
+    "standard": "^17.1.0",
+    "supertest": "6.3.3"
+  },
+  "files": [
+    "lib/",
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 18"
+  },
+  "scripts": {
+    "lint": "standard",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test:debug": "mocha --reporter spec --bail --check-leaks test/ --inspect --inspect-brk",
+    "test-ci": "nyc --reporter=lcov --reporter=text npm test",
+    "test-cov": "nyc --reporter=text npm test",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
+  }
+}