Source openbabel from danagroup channel for Python 3.14

conda-forge doesn't have openbabel built for Python 3.14.
Use danagroup::openbabel which provides a 3.14-compatible build.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: alongd

environment.yml

@@ -2,6 +2,7 @@ name: arc_env
 
 channels:
   - conda-forge
+  - danagroup
 
 dependencies:
   # ─── core ─────────────────────────────────────
@@ -31,6 +32,7 @@ dependencies:
   - conda-forge::mako
   - conda-forge::matplotlib
   - conda-forge::networkx
+  - danagroup::openbabel >=3
   - conda-forge::pandas
   - conda-forge::paramiko >=2.6.0
   - conda-forge::py3dmol >=0.8.0