What problem does it solve? Running the Helios FHIR Server requires navigating dozens of environment variables, storage backend modes, and behavior flags, and misconfiguration leads to startup failures or incorrect tenant routing. ## Core Features & Use Cases - Server Startup & Configuration: Launch the hfs binary with SQLite, PostgreSQL, Elasticsearch, or S3 storage backends using HFS environment variables. - Multi-Tenancy & Routing: Configure tenant routing via headers or URL paths, with strict validation options and JWT claim support. - Operational Tuning: Control compression, CORS, request limits, pagination, versioning, and dashboard refresh intervals. - Use Case: A developer needs to run HFS against PostgreSQL with Elasticsearch search and debug why search results lag behind writes; the skill provides the exact backend mode, connection variables, and the HFS_COMPOSITE_SYNC_MODE=synchronous setting for read-your-write semantics. ## Quick Start Start the HFS FHIR server locally with the default SQLite backend and show me how to switch it to PostgreSQL using environment variables.