[CORL-836] Create activeStories endpoint (#2787)

* Create activeStories GraphQL query endpoint

Set lastCommentedAt on stories when they are
commented upon.
Use lastCommentedAt to retrieve the activeStories.
Create a migration to partial index
lastCommentedAt on stories to make retrieval fast.

CORL-836

* fix: adjusted query to use index, more @auth directives

Co-authored-by: Wyatt Johnson <accounts+github@wyattjoh.ca>

src/core/server/graph/resolvers/Query.ts

@@ -21,4 +21,6 @@ export const Query: Required<GQLQueryTypeResolver<void>> = {
   debugScrapeStoryMetadata: (source, { url }, ctx) =>
     ctx.loaders.Stories.debugScrapeMetadata.load(url),
   moderationQueues: moderationQueuesResolver,
+  activeStories: (source, { limit = 10 }, ctx) =>
+    ctx.loaders.Stories.activeStories(limit),
 };