Overflowing rounds go first again (solidcore#1980)

OVERFLOW_GOES_FIRST on. The rig shows no wrong volume: 5158's plate keeps its
value and 1080-notched-r8 moves to within 7e-11 of the C++ kernel. The sloped basin's
R4 rounds are refused as in the C++ kernel at 2fc375f.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MNXLXkZLQ6T7TSi4wswcmk

crates/smlib/src/core/blend.rs

@@ -542,12 +542,10 @@ fn picked_on(b: &Brep, e: EdgeId) -> Option<(solidcore::geom::attribute::Attribu
     a.application_value::<Picked>().map(|p| (h, p.0))
 }
 
-/// Whether the rounds that overflow go first ([`overflow_first`]), held back: solidcore's
-/// `SubtractRemovalRegion` loses the attributes of target edges the subtraction replaces, so a picked
-/// edge the overflow only shortened reads as removed whole and is silently left unrounded (the rig's
-/// fillets/5158-fillet-adjacent-plate-edges-as-thick-as-plate, 1706.89 against 1681.90). Off, the
-/// rounds are blended together, and those that need the order are refused.
-const OVERFLOW_GOES_FIRST: bool = false;
+/// Whether the rounds that overflow go first ([`overflow_first`]): on since solidcore#1980, which
+/// keeps the attributes of the target edges the subtraction replaces, so a picked edge the overflow
+/// only shortened still reads as picked.
+const OVERFLOW_GOES_FIRST: bool = true;
 
 /// `overflow_first`: the rounds of [`blend_call`] when blends of several edges overflow their
 /// faces (`round_edges` stopped in the copy `w` of `body`, `picked` its picked edges, `each` their

crates/smlib/src/core/blend_tests.rs

@@ -433,7 +433,6 @@ fn a_cliff_overflow_the_fork_refuses_has_no_room() {
 /// the back upright that upright's round runs above the R21 cylinder, taking the corner's piece
 /// over it too (Simpson on 4000 spans, against a bound of its quartic end edge's tolerance).
 #[test]
-#[ignore = "core::blend::OVERFLOW_GOES_FIRST is held back: solidcore's cliff overflow loses edge attributes (an_edge_tag_crosses_a_cliff_overflow). Passes with it on: 6107.529369565"]
 fn overflow_goes_first() {
     let f = |u: f64| 0.5 * (u * (441.0 - u * u).sqrt() + 441.0 * (u / 21.0).asin());
     let w = 440f64.sqrt();