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>

lib/berrypod_web/controllers/health_controller.ex

@@ -0,0 +1,7 @@
+defmodule BerrypodWeb.HealthController do
+  use BerrypodWeb, :controller
+
+  def show(conn, _params) do
+    json(conn, %{status: "ok"})
+  end
+end