After rewind/cache-miss the keyed visible row stayed distinct from the
persistent parser candidate, so every later growth frame deep-cloned the
parser DOM into the old row. That cut off the previous tail word's
~620ms fade and broke word-node identity.
Promote the parser-owned candidate into the existing row's DOM position
once, mute the already-rendered prefix on the real parser body, and
return the adopted node so later keyed renders hit existing === node.
Regression: two post-transition growth frames keep the first new tail
span as the same .is-new node until an explicit animationend.
Anthony Ruiz
69e4fa3b98
