HTTP API
Everything the editor can do, Glider can do over HTTP.
Validation over HTTP, for CI.
POST /api/pages/<id>/wiring # would it paint?
GET /api/pages/<id>/structure # names, groups, nesting
POST /api/pages/<id>/unit-check # unit schema, expressions, writers
Each returns a report with issues carrying a level of failure, warning or info. Wire them into CI to catch a broken page before someone tries to take it.