feat: enhance Safew error handling and polling mechanism

- Added error_msg field to safewAPIResponse for better error descriptions.
- Updated safewErrorDescription function to include error_msg in the output.
- Introduced a new test to verify that error messages are included in Safew error descriptions.
- Improved the polling mechanism in the Watcher to handle conflicts and ensure no overlapping polls occur.

internal/adapter/safew_chats_test.go

@@ -99,6 +99,13 @@ func TestPollGroupChatsSuccess(t *testing.T) {
 	}
 }
 
+func TestSafewErrorDescriptionIncludesErrorMsg(t *testing.T) {
+	got := safewErrorDescription([]byte(`{"ok":false,"description":"BAD_REQUEST","error_msg":"Conflict: terminated by other getUpdates request"}`))
+	if !strings.Contains(got, "Conflict") {
+		t.Fatalf("got %q, want error_msg", got)
+	}
+}
+
 func TestPollGroupChatsUnauthorized(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusUnauthorized)