fix: unlink the ankle cuffs, stop the reload head-dive, soften every blend

Three animation complaints, measured before changing anything.

There is NO squash-and-stretch. Instrumented every bone every frame: the
worst deviation of a pose basis from a pure rotation is 0.00000. Every clip's
position tracks match the skeleton's rest pose to within a millimetre (only
DEF-hips translates, as it should) and no scale key deviates from 1. The
"squishing" is a deep BEND, not a scale: the shared library's PistolReload was
authored for someone watching their own hands, and it dives the head 33° with
the whole neck chain at 67°. At that depth Taila's head/hair weights pinch and
the skull changes shape. Dropping neck+head from the upper-body one-shot's
filter leaves them on the locomotion layer: head dive is now 14° and the neck
chain 48°, and the character keeps looking downrange through a reload, which
is what a shooter wants anyway. Trade-off: Throw/Hit no longer swing the head.

The ankle cuffs are not linked by the rig or the clips — the foot bones swing
independently (left/right Z correlation -0.94). They are linked by SKIN
WEIGHTS: 16 vertices belonging to the LEFT cuff, sitting at x = -0.002 just
across the centre line, are weighted to the RIGHT leg, so the far foot drags a
band of cuff across the gap. Position alone cannot classify them (the cuff
they belong to spans x = 0.00 .. 0.05), so SkinWeightRepair decides by
CONNECTIVITY: a vertex that disagrees with 80%+ of the vertices it shares
triangles with gets its leg influences mirrored. Ankle-height cross-leg
triangles go 24 -> 0 on Taila; the pass is conservative enough that Miku needs
exactly 1 vertex and her face/hair/skirt are untouched (only leg bones are
ever considered). Meshes with blend shapes are skipped rather than rebuilt.

Blending: nothing cuts hard any more. Base cross-fade 0.15 -> 0.22, locomotion
0.28-0.30 (Idle/Walk/Run/Sprint switch constantly as speed drifts across their
thresholds, which is where the snapping showed most), reaction moves raised
off their near-instant values but still snappy, and the upper-body one-shot's
own fades widened to 0.14 in / 0.22 out.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

debug/character_look_capture.gd.uid

@@ -0,0 +1 @@
+uid://dacludfhqj3fb