feat(opencode): add OpenUltraSAST steering skills

tests/test_opencode_skills.py

@@ -0,0 +1,20 @@
+from pathlib import Path
+
+
+def test_project_opencode_skills_have_required_frontmatter() -> None:
+    skills_root = Path(".opencode/skills")
+    skill_files = sorted(skills_root.glob("*/SKILL.md"))
+
+    assert {path.parent.name for path in skill_files} == {
+        "openultrasast-fix-audit",
+        "openultrasast-kiro-impl",
+        "openultrasast-scan",
+        "openultrasast-triage",
+    }
+
+    for skill_file in skill_files:
+        text = skill_file.read_text()
+        header = text.split("---", 2)[1]
+        assert f"name: {skill_file.parent.name}" in header
+        assert "description: " in header
+        assert "Use when" in header