feat: add feed sidebar and cursor-based pagination

Add a feed sidebar to /unread and /read pages for filtering articles by
feed, and replace the fixed 100-article limit with cursor-based
pagination using a "Load more" button.

Backend:
- Add PageInfo, ArticleConnection types and pagination args to GraphQL
- Replace GetUnreadArticles/GetReadArticles with parameterized queries
- Add GetFeedUnreadCounts query and composite index
- Add shared pagination helper in resolver

Frontend:
- Add FeedSidebar component with unread count badges
- Add usePaginatedArticles hook for cursor-based fetching
- Update ArticleList with Load more button and single-feed mode
- Use ?feed=<id> query parameter for feed filtering

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/backend/graphql/model/generated.go b/backend/graphql/model/generated.go
index 11f9692..a305535 100644
--- a/backend/graphql/model/generated.go
+++ b/backend/graphql/model/generated.go
@@ -20,6 +20,14 @@ type Article struct {
 	Feed *Feed `json:"feed"`
 }
 
+// A paginated list of articles
+type ArticleConnection struct {
+	// The list of articles
+	Articles []*Article `json:"articles"`
+	// Pagination information
+	PageInfo *PageInfo `json:"pageInfo"`
+}
+
 // Authentication payload returned from login mutation
 type AuthPayload struct {
 	// The authenticated user
@@ -38,6 +46,8 @@ type Feed struct {
 	FetchedAt string `json:"fetchedAt"`
 	// Whether the user is currently subscribed to this feed
 	IsSubscribed bool `json:"isSubscribed"`
+	// Number of unread articles in this feed
+	UnreadCount int32 `json:"unreadCount"`
 	// Articles belonging to this feed
 	Articles []*Article `json:"articles"`
 }
@@ -46,6 +56,14 @@ type Feed struct {
 type Mutation struct {
 }
 
+// Pagination information for cursor-based pagination
+type PageInfo struct {
+	// Whether there are more items after the last item in this page
+	HasNextPage bool `json:"hasNextPage"`
+	// Cursor of the last item in this page
+	EndCursor *string `json:"endCursor,omitempty"`
+}
+
 // Root query type for reading data
 type Query struct {
 }