ie-html: refine adoption agency and formatting element handling

[thomasnemer]

Goal

Fix adoption agency edge cases. Currently adoption tests pass ~50%.

Affected test files

• adoption01.dat: 9/17 (53%)
• adoption02.dat: 1/2 (50%)
• tricky01.dat: 0/9 (0%)
• tests26.dat: 1/20 (5%)

Implementation needed

• Review adoption agency inner loop boundary conditions
• Fix element replacement and reparenting ordering
• Handle formatting elements across table boundaries
• Fix active formatting marker handling at scope boundaries

Estimated impact

+30-50 tests passing