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.
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.