chore: import upstream snapshot with attribution

tests/test_antigravity_install.py

@@ -0,0 +1,28 @@
+"""Antigravity install lays down its full always-on layer, not just the skill.
+
+Regression: project-scoped `install --project --platform antigravity` previously
+went through the skill-only branch (grouped with copilot/pi/kimi), so it copied
+the SKILL.md but never wrote `.agents/rules/graphify.md` or
+`.agents/workflows/graphify.md` - even though the uninstall path removes them.
+"""
+import graphify.__main__ as m
+
+
+def test_antigravity_project_install_writes_rules_and_workflows(tmp_path):
+    m._project_install("antigravity", tmp_path)
+    skill = tmp_path / ".agents" / "skills" / "graphify" / "SKILL.md"
+    rules = tmp_path / ".agents" / "rules" / "graphify.md"
+    workflow = tmp_path / ".agents" / "workflows" / "graphify.md"
+    assert skill.exists(), "skill should be installed under .agents/skills/"
+    assert rules.exists(), "antigravity rules (always-on) must be written"
+    assert workflow.exists(), "antigravity workflow must be written"
+    # native tool-discovery frontmatter is injected into the skill
+    assert skill.read_text(encoding="utf-8").startswith("---\n")
+
+
+def test_antigravity_project_uninstall_clears_rules_and_workflows(tmp_path):
+    m._project_install("antigravity", tmp_path)
+    m._project_uninstall("antigravity", tmp_path)
+    assert not (tmp_path / ".agents" / "rules" / "graphify.md").exists()
+    assert not (tmp_path / ".agents" / "workflows" / "graphify.md").exists()
+    assert not (tmp_path / ".agents" / "skills" / "graphify" / "SKILL.md").exists()