🗑️ remove(tsl): drop syntax_book/, data/ source and build script

- Remove docs/tsl/syntax_book/ (superseded by docs/tsl/syntax/)
- Remove data/tsl_reference_catalog_source/ (catalog already generated
  into docs/tsl/reference/catalog/, source no longer needed)
- Remove scripts/build_tsl_reference_catalog.ps1 (build script for
  the above source)
- Remove test assertion that referenced the deleted data/ source index

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_tsl_entrypoints_consistency.py

@@ -8,8 +8,6 @@ PLAYBOOK_EXAMPLE = ROOT / "playbook.toml.example"
 SKILLS_DOC = ROOT / "SKILLS.md"
 TEMPLATES_CI_README = ROOT / "templates" / "ci" / "README.md"
 REMOVED_TSL_GUIDE = ROOT / "codex" / "skills" / "tsl-guide"
-REFERENCE_CATALOG_SOURCE_INDEX = ROOT / "data" / "tsl_reference_catalog_source" / "index.md"
-
 
 class TslEntrypointsConsistencyTests(unittest.TestCase):
     def test_ruleset_lists_canonical_tsl_layers(self):
@@ -52,11 +50,6 @@ class TslEntrypointsConsistencyTests(unittest.TestCase):
         self.assertNotIn("tsl-guide", SKILLS_DOC.read_text(encoding="utf-8"))
         self.assertNotIn("$tsl-guide", RULESET_TSL.read_text(encoding="utf-8"))
 
-    def test_reference_catalog_source_index_uses_canonical_reference_entrypoint(self):
-        text = REFERENCE_CATALOG_SOURCE_INDEX.read_text(encoding="utf-8")
-        self.assertIn("docs/tsl/reference/catalog/index.md", text)
-        self.assertNotIn("docs/tsl/syntax_book/function/index.md", text)
-
 
 if __name__ == "__main__":
     unittest.main()