Test bulk export against Inferno Bulk Data test kit

[johngrimes]

Validate the Pathling bulk data export implementation against the Inferno Bulk Data Access Test Kit (v2.0.0 server suite).

The test suite validates:

• SMART Backend Services authorisation (OAuth 2.0 client credentials with asymmetric keys)
• Patient-level, Group-level, and system-level $export operations
• Asynchronous workflow (kick-off, status polling, NDJSON file download, cleanup)
• Export parameters (_type, _since, _typeFilter, etc.)

Authentication on demo.pathling.app

The Inferno test kit requires SMART Backend Services authorisation. Pathling already supports this, but demo.pathling.app currently runs without authentication enabled.

We'll need to enable authentication on the demo instance while keeping it easy to sign up (e.g. sign in with GitHub). This would involve setting up an identity provider and configuring Pathling's authorisation layer to use it.

Tasks

• Enable authentication on demo.pathling.app with an easy sign-up flow (e.g. GitHub OAuth)
• Configure SMART Backend Services authorisation on the instance
• Register Inferno's JWK Set for client authentication
• Run the Inferno Bulk Data v2.0.0 server test suite
• Identify and fix any conformance gaps