feat: initial art assets

- cat.jpg: foundational image
- cat-copy.jpg: minted via identity-cat recipe
- cat-copy.provenance.json: full provenance chain

Owner: @giles@artdag.rose-ash.com

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -0,0 +1,21 @@
+# Art DAG - Art Assets
+
+Content-addressed art storage. URLs use commit hashes for immutability.
+
+## Assets
+
+| Name | Hash | File |
+|------|------|------|
+| cat | `33268b6e...` | cat.jpg |
+| cat-copy | `33268b6e...` | cat-copy.jpg (minted via identity-cat recipe) |
+
+## Immutable URLs
+
+Use commit hash in URL for permanent reference:
+```
+https://git.rose-ash.com/art-dag/art/raw/{COMMIT_HASH}/cat.jpg
+```
+
+## Owner
+
+`@giles@artdag.rose-ash.com`