Changes in version 0.0.0.9000                      

New Features

  - add_healthcheck() registers healthcheck endpoints on any Shiny app
    object by decorating its internal HTTP handler -- no uiPattern
    changes, no plumber sidecar, no second port. Registrations stack for
    separate liveness/readiness endpoints, handler errors are converted
    into machine-readable 503 responses, and verbose (default:
    shiny::in_devmode()) logs probe hits to the console.
  - health_response() creates health_response objects (classed
    shiny::httpResponse()s) with best practice defaults:
    application/health+json content type, Cache-Control: no-store,
    RFC 3339 UTC timestamps, and independent body status / HTTP
    status_code semantics. Includes the full S3 triad
    (new_health_response(), validate_health_response(),
    is_health_response()), coercion via as_health_response(), and
    cli-formatted print()/format()/str() methods.
  - health_handler_default() documents and implements the healthcheck
    handler contract: any function(req) returning a health_response, a
    shiny::httpResponse, or a named list.
  - has_healthcheck() and healthcheck_paths() introspect registered
    endpoints; print() on a decorated app announces its endpoints before
    launching.
  - ts_utc() formats RFC 3339 / ISO 8601 UTC timestamps.
  - A runnable example app ships under inst/shiny/hello.

Testing

  - Three-tier test suite: pure unit tests, app-object introspection
    tests, and live wire tests against a real running app (non-blocking
    shiny::startApp() with promise-based requests), including a
    cross-process probe test matching real orchestrator behavior.