Add listActions() and executeAction() to FeedSource for write
operations back to external services. Actions use arktype schemas
for input validation via StandardSchemaV1.
- ActionDefinition type with optional input schema
- FeedEngine routes actions with existence and ID validation
- Source IDs use reverse-domain format (aris.location, aris.tfl)
- LocationSource: update-location action with schema validation
- TflSource: set-lines-of-interest action with lineId validation
- No-op implementations for sources without actions
Co-authored-by: Ona <no-reply@ona.com>
Sources that cannot provide context now return null
instead of omitting the method. The engine checks the
return value rather than method existence.
Co-authored-by: Ona <no-reply@ona.com>
Introduces FeedEngine that consumes FeedSource instances and manages
the dependency graph for context flow and item collection.
- Validates dependency graph (missing deps, circular references)
- Topologically sorts sources for execution order
- Runs fetchContext() in dependency order, accumulating context
- Runs fetchItems() on all sources with final context
- Supports reactive updates via onContextUpdate/onItemsUpdate
- Graceful error handling (continues after source failures)
Marks DataSource, ContextProvider, ContextBridge, Reconciler, and
FeedController as deprecated in favor of FeedSource + FeedEngine.
Co-authored-by: Ona <no-reply@ona.com>
