Drop legacy yaml/tag info string; tag blocks now require
```yaml role=tag. Add fence-line tag=/id= attributes that
override YAML body values, and move parseBlockAttrs to
src/markdown/block-attrs.ts so scanner and render extensions
share one parser.
Accept yaml role=tag alongside legacy yaml/tag so the block
body gets yaml syntax highlighting, matching the CLI role=
attribute convention. Copy button now emits the role=tag form.
Add a unique `_key` to each layer config to maintain stable sortable IDs
across reorder operations. Update LayerRow to use the sortableId prop
and the `use:sortable` directive. Refactor layer-crud utilities to
generate and propagate `_key` values on creation and initialization.
hypercross
hyper