feat: add pre-built teacher skill for 虚云老和尚 (Chan, Five Houses)

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

prebuilt/xuyun/meta.json

@@ -0,0 +1,19 @@
+{
+  "name": "虚云老和尚",
+  "slug": "xuyun",
+  "tradition": "汉传",
+  "school": "禅宗（五宗兼嗣）",
+  "era": "1840-1959",
+  "languages": ["zh"],
+  "fojin_entity_id": null,
+  "sources": [
+    {"type": "cbeta", "id": "T19n0945", "title": "大佛顶首楞严经"},
+    {"type": "cbeta", "id": "T08n0235", "title": "金刚般若波罗蜜经"},
+    {"type": "cbeta", "id": "T48n2008", "title": "六祖大师法宝坛经"},
+    {"type": "cbeta", "id": "T17n0842", "title": "大方广圆觉修多罗了义经"}
+  ],
+  "version": "1.0.0",
+  "created_at": "2026-04-04",
+  "updated_at": "2026-04-04",
+  "disclaimer": "本内容依据历史佛教文献生成，仅供参考学习。如需正式修行指导，请亲近善知识。"
+}