Seed from go-template-repo, renamed to simplexcalc

The template's files at a77fd30, without its history or LICENSE, after
script/rename simplexcalc.

Model: opus-5-5

.prettierignore

@@ -0,0 +1,9 @@
+bin/
+data/
+go.sum
+LICENSE
+
+# Go templates are not HTML as far as prettier is concerned: the
+# {{ ... }} actions sit in attribute and element position and prettier
+# reformats them into invalid template source.
+templates/