hardBreakOwnsItsLine answers from raw sibling bytes what whitespace row A8 already recorded

Split from #325, row R2 (verified at main ffdc1860).

The question: does a hard break own its line?

The reader's answer: whitespace row A8 (src/whitespace-fact.ts, beforeHardBreak decided from the node that follows the run; a run holding a newline is bound to newline).

The second answerer: hardBreakOwnsItsLine in src/print/text-edges.ts (l.480), a multi-node walk over raw sibling values with a regex test plus two node-type arms. Four readers: src/print/inline.ts l.399, text-edges.ts l.530, src/print/list-hazard.ts l.245, and its own recursion.

Closes when: the printer reads the recorded row and hardBreakOwnsItsLine is deleted, or a written reason why the recorded row cannot answer at each of the four readers. The deletion goes in scripts/deletions.json; no new recorded fact is expected, so no parity family.

Related: #325 (the catalog), #90 (the class), #307 (row R1, the neighbouring rule).

Start with src/whitespace-fact.ts and the recorded beforeHardBreak row, then inspect the four readers in src/print/inline.ts, src/print/text-edges.ts, src/print/list-hazard.ts, and the recursive path in text-edges.ts. Confirm whether the recorded row answers each use, then remove hardBreakOwnsItsLine and record the deletion in scripts/deletions.json, or document why it must remain.