✨ feat(skills): add skill_link symlink support + platform-agnostic prompt

- Add skill_link config option to create a symlink/junction from another
  platform's skills dir to agents_home/skills/ (e.g. ~/.claude -> ~/.agents)
- On Windows, falls back to directory junction when symlink requires admin
- Add _create_skills_symlink() with _is_junction() helper for Windows
- Update playbook.toml.example with skill_link documentation
- Fix templates/README.md prompt example to be platform-agnostic
- Add 3 tests: symlink creation, idempotency, absence when unconfigured

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

scripts/playbook.py

@@ -22,7 +22,7 @@ ORDER = [
 ]
 SCRIPT_DIR = Path(__file__).resolve().parent
 PLAYBOOK_ROOT = SCRIPT_DIR.parent
-PATH_CONFIG_KEYS = {"project_root", "deploy_root", "agents_home", "codex_home"}
+PATH_CONFIG_KEYS = {"project_root", "deploy_root", "agents_home", "codex_home", "skill_link"}
 DOCS_INDEX_SECTION_HEADINGS = {
     "common": "## 跨语言（common）",
     "tsl": "## TSL（tsl/tsf）",
@@ -1244,9 +1244,57 @@ def install_skills_action(config: dict, context: dict) -> int:
         tag = " [thirdparty]" if origin == "thirdparty" else ""
         log(f"Installed: {name}{tag}")
 
+    skill_link_raw = config.get("skill_link")
+    if skill_link_raw:
+        skill_link_home = Path(str(skill_link_raw)).expanduser()
+        if not skill_link_home.is_absolute():
+            skill_link_home = (context["project_root"] / skill_link_home).resolve()
+        _create_skills_symlink(skill_link_home / "skills", skills_dst_root)
+
     return 0
 
 
+def _is_junction(path: Path) -> bool:
+    if sys.platform != "win32":
+        return False
+    try:
+        import ctypes.wintypes
+        attrs = ctypes.windll.kernel32.GetFileAttributesW(str(path))
+        return attrs != -1 and bool(attrs & 0x400)
+    except Exception:
+        return False
+
+
+def _create_skills_symlink(link_path: Path, target_path: Path) -> None:
+    if link_path.is_symlink() or _is_junction(link_path):
+        if link_path.resolve() == target_path.resolve():
+            log(f"Symlink already up to date: {link_path}")
+            return
+        if link_path.is_symlink():
+            link_path.unlink()
+        elif _is_junction(link_path):
+            link_path.rmdir()
+    elif link_path.exists():
+        log(f"Skip symlink: {link_path} exists and is not a symlink")
+        return
+    ensure_dir(link_path.parent)
+    try:
+        link_path.symlink_to(target_path, target_is_directory=True)
+        log(f"Created symlink: {link_path} -> {target_path}")
+    except OSError:
+        if sys.platform == "win32":
+            result = subprocess.run(
+                ["cmd", "/c", "mklink", "/J", str(link_path), str(target_path)],
+                capture_output=True,
+            )
+            if result.returncode == 0:
+                log(f"Created junction: {link_path} -> {target_path}")
+            else:
+                log(f"Warning: could not create junction {link_path}")
+        else:
+            log(f"Warning: could not create symlink {link_path}")
+
+
 def format_md_action(config: dict, context: dict) -> int:
     tool = str(config.get("tool", "prettier")).lower()
     if tool != "prettier":