Merge fix/install-keep-skills-dir into master

scripts/install.sh

@@ -40,8 +40,8 @@ fi
 
 for dst in "${TARGET}/.agents/skills" "${TARGET}/.claude/skills"; do
 	log "skills: copying -> ${dst}"
-	rm -rf "${dst}"
 	mkdir -p "${dst}"
+	find "${dst}" -mindepth 1 -delete
 	cp -a "${src}/." "${dst}/"
 done
 

tests/test_install.py

@@ -0,0 +1,42 @@
+"""Pin scripts/install.sh: the installed skill directories keep their inode, so a bind mount of them stays current."""
+
+from __future__ import annotations
+
+import os
+import shutil
+import subprocess
+import tempfile
+import unittest
+from pathlib import Path
+
+INSTALL = Path(__file__).resolve().parents[1] / "scripts" / "install.sh"
+NPX = "#!/bin/sh\nmkdir -p .agents/skills/locked\necho locked > .agents/skills/locked/SKILL.md\n"
+
+
+class TestInstall(unittest.TestCase):
+    def test_reinstall_empties_the_skill_directories_in_place(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            root = Path(tmp)
+            repo, target, stubs = root / "repo", root / "target", root / "bin"
+            (repo / "scripts").mkdir(parents=True)
+            shutil.copy(INSTALL, repo / "scripts" / "install.sh")
+            (repo / "scripts" / "enable-plugins.js").write_text("", encoding="utf-8")
+            (repo / "skills" / "own").mkdir(parents=True)
+            (repo / "skills" / "own" / "SKILL.md").write_text("own", encoding="utf-8")
+            stubs.mkdir()
+            (stubs / "npx").write_text(NPX, encoding="utf-8")
+            (stubs / "npx").chmod(0o755)
+            installed = [target / ".agents" / "skills", target / ".claude" / "skills"]
+            for folder in installed:
+                (folder / "stale").mkdir(parents=True)
+            before = [folder.stat().st_ino for folder in installed]
+            env = {**os.environ, "PATH": f"{stubs}:/usr/bin:/bin", "TARGET": str(target)}
+            done = subprocess.run(["bash", str(repo / "scripts" / "install.sh")], env=env, capture_output=True, text=True, check=False)
+            self.assertEqual(done.returncode, 0, done.stderr)
+            self.assertEqual([folder.stat().st_ino for folder in installed], before)
+            for folder in installed:
+                self.assertEqual(sorted(path.name for path in folder.iterdir()), ["locked", "own"])
+
+
+if __name__ == "__main__":
+    unittest.main()