feat(poly): find all connected elements to central vertex

In order to constrain the central slope we find all the elements connected to the central vertex. The slope will be approximated over these using the finite difference method

meson.build

@@ -1,3 +1,23 @@
+# ***********************************************************************
+#
+#   Copyright (C) 2025 -- The 4D-STAR Collaboration
+#   File Author: Emily Boudreaux
+#   Last Modified: March 19, 2025
+#
+#   4DSSE is free software; you can use it and/or modify
+#   it under the terms and restrictions the GNU General Library Public
+#   License version 3 (GPLv3) as published by the Free Software Foundation.
+#
+#   4DSSE is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#   See the GNU Library General Public License for more details.
+#
+#   You should have received a copy of the GNU Library General Public License
+#   along with this software; if not, write to the Free Software
+#   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+#
+# *********************************************************************** #
 project('4DSSE', 'cpp', version: '0.0.1a', default_options: ['cpp_std=c++23'], meson_version: '>=1.6.0')
 
 # Add default visibility for all C++ targets