Fix UUID cast in task creation, add kind test manifests

- Fix parent_task_id NULLIF cast to UUID type in INSERT query
- Fix itoa helper to use strconv.Itoa
- Handle AddReaction errors gracefully in webhook handler
- Add hack/kind/ manifests for local testing with kind cluster

internal/apiserver/handlers/webhook.go

@@ -84,7 +84,9 @@ func (h *WebhookHandler) HandleGitea(w http.ResponseWriter, r *http.Request) {
 			"author", event.Author,
 		)
 
-		h.provider.AddReaction(parts[0], parts[1], event.CommentID, "eyes")
+		if err := h.provider.AddReaction(parts[0], parts[1], event.CommentID, "eyes"); err != nil {
+			slog.Warn("failed to add reaction", "error", err)
+		}
 	}
 
 	w.WriteHeader(http.StatusAccepted)