v0.28.1

Fixed

• Fused multi-paragraph tweet writes no longer corrupt docs. Agent writes and Author's Voice rewrites delivered as TipTap JSON bypassed the markdown parser's <br><br> paragraph-split heal, so an X-style fused paragraph (one node with double hardBreaks) could enter canonical content — breaking the serialize→reparse round-trip (sync-check failures), destabilizing the node-identity matcher, and corrupting pending decorations (phantom single-word "original" highlight + duplicated/orphaned nodes). write_to_pad and populate_document now run the same split heal on structured/JSON content as the markdown path. Idempotent; editor, parser, and serializer unchanged.