chore: empty changeset (docs/skill only, no package release)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: os-zhuang

.changeset/adr-0046-doc-guide-skill.md

@@ -0,0 +1,7 @@
+---
+---
+
+docs(metadata): ADR-0046 — add the `doc`-type authoring guide
+(`content/docs/guides/metadata/doc.mdx` + index/sidebar) and cover package
+docs in the objectstack-ui skill. Documentation and AI-skill content only;
+no package release.