Carry optional span positions through the schema, WASM header, editor,
Plugin API and CSS output. Expose Chinese controls with language defaults
and independent overrides for horizontal and vertical text.
Reserve automatic clearance per side and stack underlines, ruby and
emphasis. Preserve reading groups during decoration edits and retain
canonical position values in DOM editor style data.
Add protocol, geometry, editing and API tests, including the prior Japanese
mixed-font gutter behavior. Verify both WASM targets and live exports.
AI-assisted-by: GPT-6
Render Japanese annotations in HTML and SVG and expose their styles
in CSS code generation. Preserve vertical position data from WASM,
while keeping the legacy SVG renderer on its horizontal layout path.
Cover generated markup, styles and copied SVG output.
