feat: deepen skill test coverage — 52 → 247 cases across all 43 skills

Add 195 new test cases covering examples from SKILL.md, edge cases,
and parameter combinations. Create _skill.json for form-edit, skd-edit,
subsystem-edit. Add fixtures for negative validate cases. Fix
normalizeUuids in meta-validate/meta-info configs.

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

tests/skills/cases/mxl-compile/minimal.json

@@ -0,0 +1,18 @@
+{
+  "name": "Минимальный макет — одна область, одна ячейка",
+  "input": {
+    "columns": 1,
+    "areas": [
+      {
+        "name": "Ячейка",
+        "rows": [
+          { "cells": [{ "col": 1, "text": "Значение" }] }
+        ]
+      }
+    ]
+  },
+  "params": { "outputPath": "Template.xml" },
+  "expect": {
+    "files": ["Template.xml"]
+  }
+}