* test(#3945): 0-of-0 milestone counters must not render complete
Regression coverage for the string-truthiness vacuous equality in both
statusline renderers: '0' counters, boundary 1/1 vs 0/1 vs 1/0, compact
parity.
* fix(#3945): require a non-empty denominator for milestone-complete
Both statusline renderers compared the regex-captured string counters
directly, so '0' && '0' && '0' === '0' fired Scene 3 on the empty set.
Numeric coercion plus total > 0 restores the guard's intent; all
non-zero shapes and percent=100 render byte-identically.
* chore(#3945): add changeset fragment
* chore(#3945): backfill changeset pr number
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Co-authored-by: sim <sim@local>
4c6643a8d7