docs(website): add scoped agent instructions

Author: pront

website/AGENTS.md

@@ -0,0 +1,24 @@
+# Vector Website Development
+
+These instructions apply to changes under `website/`. See [README.md](README.md)
+for the website architecture and prerequisites.
+
+Target website changes to `master`.
+
+Run the site locally from the repository root:
+
+```bash
+make generate-docs
+cd website
+make serve
+```
+
+The local site is available at <http://localhost:1313>.
+
+Build CUE documentation from the `website/` directory:
+
+```bash
+make cue-build
+```
+
+After editing Markdown, run `make check-markdown` from the repository root.

website/CLAUDE.md

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+@AGENTS.md