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/_skill.json

@@ -0,0 +1,12 @@
+{
+  "script": "meta-compile/scripts/meta-compile",
+  "setup": "empty-config",
+  "args": [
+    { "flag": "-JsonPath", "from": "inputFile" },
+    { "flag": "-OutputDir", "from": "workDir" }
+  ],
+  "snapshot": {
+    "root": "workDir",
+    "normalizeUuids": true
+  }
+}