predicate alignment

Canonical: `ex:when`

Predicates from the live registry whose trigram similarity to ex:when is ≥ 0.55. Selecting an alias rewrites every live statement using it so it uses the canonical predicate instead, and files a closeMatch fact under ctx:user/merges.

tighter (0.45) · looser-only (0.70)

Predicate	Similarity	Live statements
`ex:even_when`	0.727	1
`ex:seen_when`	0.667	2
`when`	0.625	21
`ex:done_when`	0.615	6
`ex:given_when`	0.615	4
`ex:held_when`	0.615	2
`ex:left_when`	0.615	2
`ex:ended_when`	0.615	2
`ex:told_when`	0.615	2
`ex:exwhen`	0.600	1
`ex:built_when`	0.571	2
`ex:worked_when`	0.571	2
`ex:arise_when`	0.571	2
`ex:stolen_when`	0.571	2

Canonical: ex:when

Canonical: `ex:when`