sortByDocOrder ties unplaceable refs to position zero, reordering stored phrase tokens

sortByDocOrder scores a ref the order map cannot place as 0:

(a, b) => (tokenDocOrder.get(a.tokenRef) ?? 0) - (tokenDocOrder.get(b.tokenRef) ?? 0)

so it ties with whatever sits at position zero rather than sorting to a place of its own. The sort is stable, so a stranded ref lands second, not first:

sort keys : 0, 1, 0
input     : tok-a, tok-b, tok-z   (tok-z stranded)
sorted    : tok-a, tok-z, tok-b

Stranded refs are ordinary rather than hypothetical: Token.ref is `${sid}:${charStart}` (src/parsers/papi/bookTokenizer.ts), the book is re-tokenized from the current USJ on every load (src/hooks/useInterlinearizerBookData.ts), and the analysis persists separately, so any upstream text edit strands every ref after it. See #136.

Where it reaches stored data

splitPhraseAtBoundary (via sliceAtBoundary), the merge updatePhrase calls in TokenLinkIcon, and PhraseBox's edit-mode writes all sort through this helper before writing. A split or merge on a phrase holding a stranded member can therefore write a token list whose order no longer matches document order.

Severity is moderated by the fact that such a phrase is already half-broken: the stranded member never renders, so the reordering moves a snapshot nobody can see. It is worth fixing because it is cheap, and because the next reader will not expect it.

Fix

Decorate-sort-undecorate: give an unplaceable token the order of the last placeable one before it, so it holds its stored position instead of tying with position zero.

src/utils/phrase-text.ts already took this position by not re-sorting at all (ba23de3, #329) — the label it builds reads the phrase link's stored order, which every writer sets to document order. This issue generalizes that for the callers that must sort.

Also check src/utils/segmentation.ts:105, which repeats the same (order.get(a) ?? 0) - (order.get(b) ?? 0) pattern.

Size: S

Priority: P3 — latent. #136's re-anchoring would reduce but not remove the exposure, since unmatched links stay stale and their refs stay stranded.

Start with sortByDocOrder and trace its callers, especially splitPhraseAtBoundary, updatePhrase in TokenLinkIcon, and PhraseBox edit-mode writes. Compare the matching sort in src/utils/segmentation.ts:105 and review src/utils/phrase-text.ts for the existing stored-order approach. Done means stranded refs retain their stored position without tying with position zero in either sorting path.