feat: combine TFL alerts into single feed item (#107)

TflSource.fetchItems() now returns one TflStatusFeedItem with an
alerts array instead of separate items per line disruption. Signals
use the highest severity. Alerts sorted by station distance.

Co-authored-by: Ona <no-reply@ona.com>

packages/aelis-source-tfl/src/index.ts

@@ -10,5 +10,7 @@ export {
 	type TflAlertSeverity,
 	type TflLineStatus,
 	type TflSourceOptions,
+	type TflStatusData,
+	type TflStatusFeedItem,
 } from "./types.ts"
-export { renderTflAlert } from "./renderer.tsx"
+export { renderTflStatus } from "./renderer.tsx"