fix(layout): leave a section holding an object in a switch unsupported in the page estimate

[airmang]

Summary

• A chart is saved in a run's hp:switch, with the OLE object standing for it in hp:default. Hancom Office lays such an object out like any other: wrapped square, it narrows the lines beside it.
• The page estimate looked for objects among a run's own children only. So it laid those lines out as if the object were not there.
• It now leaves such a section unsupported (an object in a switch (hp:switch)) rather than estimating it wrongly.

Test plan

• A paragraph holding a square-wrapped chart in a switch is reported unsupported; without the switch the document is estimated. The test fails before the change.
• Lint, format, type checks and the other repository gates
• Layout tests

🤖 Generated with Claude Code

[airmang]

Reviewed exact head 68bb443 and surrounding section-support/object discovery code. Reporting sections containing objects in a run-level hp:switch as unsupported is a conservative response to currently unmeasured wrapping; chart/default-OLE coverage and removal comparison exercise the boundary. No code defect found. Locally, 10 related switch/unsupported tests passed. All 13 exact-head checks pass; workflow SHA verified and CI test/lint/type/hygiene logs inspected (6,867 passed, 18 skipped, 1 xfailed).

Merge is held: after #499 and #501 merged, scratch integration against current main 97c2bef reproduces a CHANGELOG.md content conflict. Preserve both PR changelog entries when resolving against latest main, then revalidate the updated head. No conflict resolution was pushed and no integration-test pass is claimed for the conflicted tree.