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/@modelcontextprotocol/sdk/dist/cjs/experimental/index.d.ts

@@ -0,0 +1,13 @@
+/**
+ * Experimental MCP SDK features.
+ * WARNING: These APIs are experimental and may change without notice.
+ *
+ * Import experimental features from this module:
+ * ```typescript
+ * import { TaskStore, InMemoryTaskStore } from '@modelcontextprotocol/sdk/experimental';
+ * ```
+ *
+ * @experimental
+ */
+export * from './tasks/index.js';
+//# sourceMappingURL=index.d.ts.map