rename project from SimpleshopTheme to Berrypod

All modules, configs, paths, and references updated.
836 tests pass, zero warnings.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -23,7 +23,7 @@ erl_crash.dump
 /tmp/
 
 # Ignore package tarball (built via "mix hex.build").
-simpleshop_theme-*.tar
+berrypod-*.tar
 
 # Ignore assets that are produced by build tools.
 /priv/static/assets/