feat: add form-*, skd-*, misc tests (batches 1, 2, 10)

New skills covered:
- form-add, form-compile, form-validate, form-info (batch 1)
- skd-compile, skd-validate, skd-info (batch 2)
- help-add, template-add, template-remove, meta-remove (batch 10)

Findings: form-add/form-info path resolution inconsistency,
meta-remove self-reference requires -Force.

45 tests across 33 skills, all passing.

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

tests/skills/cases/skd-validate/valid.json

@@ -0,0 +1,11 @@
+{
+  "name": "Корректная СКД проходит валидацию",
+  "preRun": [
+    {
+      "script": "skd-compile/scripts/skd-compile",
+      "input": { "dataSets": [{ "name": "Основной", "type": "Query", "query": "SELECT 1 AS Поле" }] },
+      "args": { "-DefinitionFile": "{inputFile}", "-OutputPath": "{workDir}/Template.xml" }
+    }
+  ],
+  "params": { "templatePath": "Template.xml" }
+}