Expand align from l/c/r to a 3x3 grid with vertical prefixes:
tl/tc/tr/bl/bc/br. Vertical position renders via flex
justify-content; compact layers strings and YAML both parse the
new values, and the layer editor dropdown gains corner/edge
options.
Allow md-deck layers to render markdown templates via {{var}}
substitution instead of only CSV props. Add config.ts to normalize
a JSON data-config attribute (size, grid, shape, layers) emitted by
the yaml code-block tag, taking precedence over legacy string props.
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.
- Use createMemo for stable IDs to prevent re-renders
- Add opacity and transition styles during drag
- Remove "所有字段已添加" message when no available fields