Three Changed entries naming what a reader comparing the two forges' tags
would otherwise reconstruct: 0.5.0/0.6.0 arrived by merge and were never
released here; the carried ## 0.6.0 section is upstream's record; and the
absent 0.6.0 tag is a decision, not an omission. Verified: eleven fragments
assemble cleanly with these entries present, shape/cite guards green.
Refs #220
