fix(lint): check w.Write return value in searcher_test

Satisfies errcheck linter requirement.

Signed-off-by: Kaviru Hapuarachchi <kavirurh@gmail.com>
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Kavirubc <hapuarachchikaviru@gmail.com>

Author: Kavirubc

internal/integrations/github/searcher_test.go

@@ -67,7 +67,7 @@ func TestSearchIssues_RateLimited(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("X-Ratelimit-Remaining", "0")
 		w.WriteHeader(http.StatusForbidden)
-		w.Write([]byte(`{"message":"API rate limit exceeded"}`))
+		_, _ = w.Write([]byte(`{"message":"API rate limit exceeded"}`))
 	}))
 	defer srv.Close()