Return empty array instead of null for empty list

Initialize slice as []Item{} instead of nil so JSON output is "[]"
rather than "null" when there are no unread items.

Fixes #4

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

Author: ejholmes

main.go

@@ -125,7 +125,7 @@ func (k *KiteRSS) List(configPath string) {
 
 // ListItems fetches feeds from the given URLs and returns unread items.
 func (k *KiteRSS) ListItems(urls []string) []Item {
-	var allItems []Item
+	allItems := []Item{}
 	var mu sync.Mutex
 	var wg sync.WaitGroup
 

main_test.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"database/sql"
+	"encoding/json"
 	"testing"
 
 	"github.com/mmcdole/gofeed"
@@ -124,3 +125,28 @@ func TestMarkReadIdempotent(t *testing.T) {
 		t.Fatalf("second MarkRead failed: %v", err)
 	}
 }
+
+func TestListItemsEmptyReturnsArray(t *testing.T) {
+	db := setupTestDB(t)
+	defer db.Close()
+
+	k := &KiteRSS{
+		DB:      db,
+		Fetcher: &MockFeedFetcher{Feeds: map[string]*gofeed.Feed{}},
+		Out:     &bytes.Buffer{},
+		ErrOut:  &bytes.Buffer{},
+	}
+
+	items := k.ListItems([]string{})
+
+	// Should return empty slice, not nil
+	if items == nil {
+		t.Fatal("expected empty slice, got nil")
+	}
+
+	// JSON should be "[]" not "null"
+	out, _ := json.Marshal(items)
+	if string(out) != "[]" {
+		t.Errorf("expected JSON '[]', got '%s'", string(out))
+	}
+}