♻️ refactor(tsl): decouple skill routing from static docs

删除静态文档中对 tsl-syntax-reference / tsl-api-reference 的导航路由，
改由运行时按需自动触发；语法/API 事实的所有权与 fail-closed 约束
只保留在 rulesets/tsl/index.md 这一唯一权威载体。

- docs/tsl/index.md：删 4 行 skill 路由及重复的所有权/fail-closed 段，回归纯分流
- docs/tsl/modules/index.md：删 API 路由及指向已删 syntax 的 3 处回跳
- docs/index.md：删 skill 导航行及 2 条指向不存在文件的死 catalog 链
- docs/tsl/syntax/index.md：删除旧路径兼容 stub，不再保留任何兼容
- rulesets/tsl/index.md：删首跳 2 条 skill 导航，保留事实边界与 Fail closed
- 同步修正相关测试断言

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/cli/test_playbook_cli.py

@@ -243,21 +243,8 @@ langs = ["tsl"]
             self.assertEqual(result.returncode, 0)
             text = docs_index.read_text(encoding="utf-8")
             self.assertIn("`tsl/index.md`", text)
-            self.assertIn("tsl-syntax-reference", text)
-            self.assertIn("`tsl/reference/catalog/datawarehouse.md`", text)
             self.assertIn("`tsl/modules/index.md`", text)
-            self.assertIn("`tsl/reference/index.md`", text)
             self.assertNotIn("`tsl/syntax_book/index.md`", text)
-            self.assertTrue(
-                (
-                    root
-                    / CUSTOM_DEPLOY_ROOT
-                    / "docs"
-                    / "tsl"
-                    / "syntax"
-                    / "index.md"
-                ).is_file()
-            )
 
     def test_external_clone_requires_explicit_playbook_root(self):
         with tempfile.TemporaryDirectory() as tmp_dir: