refactor: move bundled skills tree to repo root skills/

- Relocate runtime/skills -> skills/; runtime_skills_root() prefers oclaw/skills
  with fallback to legacy runtime/skills for unmigrated trees.
- session-bootstrap hook handler resolves repo root via PROJECT_ROOT.
- Update architecture/migration docs and in-tree skill references.

Co-authored-by: Cursor <cursoragent@cursor.com>

runtime/skills/tushare-finance/metadata.json

@@ -1,19 +0,0 @@
-{
-  "name": "tushare-finance",
-  "version": "2.0.6",
-  "description": "获取中国金融市场数据（A股、港股、美股、基金、期货、债券）。支持220+个Tushare Pro接口：股票行情、财务报表、宏观经济指标。提供Python API客户端、命令行工具和批量导出功能。",
-  "author": "StanleyChanH",
-  "tags": ["金融数据", "A股", "港股", "美股", "量化", "股票", "基金", "期货", "Tushare", "财务数据", "宏观经济"],
-  "repository": "https://github.com/StanleyChanH/Tushare-Finance-Skill-for-Claude-Code",
-  "license": "Apache-2.0",
-  "dependencies": {
-    "python": ">=3.8",
-    "packages": ["tushare>=1.3.0", "pandas>=2.0.0", "openpyxl>=3.1.0"]
-  },
-  "openclaw": {
-    "requires": {
-      "bins": ["python3"],
-      "env": ["TUSHARE_TOKEN"]
-    }
-  }
-}