Add archify-vscode-ext skill: Archify diagrams and models for the Archify Diagram Viewer extension

Model tasks (validate, list, scaffold, resolve), diagram tasks (validate,
render), the bundled Archify 3.0.1 runtime and yaml parser under
scripts/vendor, references for authoring, formats and folders, and the
online-shop example model.

scripts/.scripts/model/lib/--env-vars-reader.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+# -------------------------------------------------------------------------------------
+#   archify-vscode-ext Agent Skill (MIT)
+# -------------------------------------------------------------------------------------
+
+# CLI-only module: all input comes from flags. No environment variables are read.