build: lower openmm floor to 8.3

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "uv_build"
 
 [project]
 name = "xchem-hippo"
-version = "2.0.3"
+version = "2.0.4"
 authors = [
     { name = "Max Winokan", email = "max@winokan.com" },
     { name = "Kalev Takkis", email = "ktakkis@informaticsmatters.com" },
@@ -43,7 +43,14 @@ dependencies = [
     "openpyxl>=3.1",
     "ipywidgets>=8.1",
     "networkx>=3.4",
-    "openmm>=8.4",
+    # Not imported by HIPPO -- carried for molparse, whose protonate.py imports
+    # openmm.app and pdbfixer lazily without declaring either. Floor is 8.3
+    # rather than 8.4 (which was an incidental pin-to-current, not an API
+    # requirement) so conda-forge/miniforge users on 8.3.x are not forced into a
+    # PyPI build over the top of theirs. pdbfixer itself only needs >=8.2, and
+    # the APIs molparse uses predate both. Do not pin exactly: only 8.5.x ships
+    # linux aarch64 wheels, which [tool.uv] required-environments demands.
+    "openmm>=8.3",
     "apsw>=3.51",
     "python-louvain>=0.16",
     "psycopg[binary]>=3.3",