feat: add skill regression test runner with meta-compile pilot

Snapshot-based test runner (tests/skills/runner.mjs) for verifying
skill script output. Zero dependencies, runs on any machine with
Node.js — no 1C platform needed for daily regression.

Pilot: meta-compile with 6 cases (4 positive with snapshots, 2 negative).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/skills/cases/meta-compile/enum.json

@@ -0,0 +1,11 @@
+{
+  "name": "Перечисление",
+  "input": {
+    "type": "Enum",
+    "name": "ВидыНоменклатуры",
+    "values": ["Товар", "Услуга", "Работа"]
+  },
+  "expect": {
+    "files": ["Enums/ВидыНоменклатуры.xml"]
+  }
+}