- Update setupTooltips to display data-bbox, data-block-ref, data-mcid, and data-reading-idx
- These attributes are already emitted by spans.rs but weren't being shown in tooltip
- Tooltip now shows complete span information on hover
References pdftract-3mdb7 acceptance criteria:
- Tooltip shows the data-* attrs as formatted rows
Bead-Id: pdftract-145s8
