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

script/projectname

@@ -0,0 +1,15 @@
+#!/bin/sh
+# script/projectname: output the name of this project. Our own
+# extension to scripts-to-rule-them-all. Other scripts that need the
+# name (e.g. script/docker) call this, so they can stay identical
+# across all repos.
+#
+# Seeding a new project: script/rename rewrites the name below. Nothing
+# else should hardcode it.
+set -eu
+
+main() {
+    echo "simplexcalc"
+}
+
+main "$@"