fix(showcase): wooden-barrel and wooden-bucket visual quality pass

[TMHSDigital]

Summary

Showcase visual quality pass on wooden-barrel and wooden-bucket (never passed; last report's remaining stave/hoop CG class). Round-1 inspection confirmed 12-gon identical staves, circular hoops floating off flats, circular heads leaving slots in the polygonal croze, a 12-box rope bail that never entered the ear rings, and ear cubes punching through the rim.

Both generators were rewritten so hoops, heads, and ears evaluate the same stave-chord host. Hygiene 15–19 locked. Inspection sheets stayed in .scratch/ (untracked).

wooden-barrel

Defects (round 1, every inspect view)

1. 12 identical staves, 5 mm daylight — clay, wire, joint-stave-gap
2. Circular capped-cylinder hoops floating off stave flats — joint-hoop-mid, ortho-front
3. Circular 16-gon lids leaving black triangular slots at every stave joint — joint-lid-top, ortho-top, clay rim
4. 5-ring polyline bulge, no bung — clay / three-q silhouette
5. Heads coplanar with stave ends (z-fight risk) — ortho-top, ortho-bottom

Structural fixes

• 20 staves, seed-17 width jitter, 8-ring bulge, 1.2 mm hairline GAP_M
• host_outer_r chord formula; hoops lofted on stave faces with bite/proud/chamfer (--round-band is a circle of radius_at(z))
• Heads follow the inner stave polygon via croze_xy, recessed by CHIME so stave ends stand above the lid
• Bung on the first-stave mid-face
• Named stave supports (--short-staves); head-croze gap (--float-head)
• Unique-cell UVs kept for the AABB-overlap budget; the still uses mesh normals (the bake is still gated) so the hero is not a quilt of UV islands

Hygiene (measured 4.5.11 / 5.1.2 / 5.2.1)

Axis	Declared	Measured
Base tris	6000–8500	7216 / 7216 / 7216 (was 4312)
Hygiene 15	0 loose/nonman/doubles/zero-area/ngons/zfight	0
zmin / 20 staves	16	0.0000 / 20
Head-croze gap	≤ 0.010 m	0.00698
Hoop bite	0.0012–0.008 m	0.00300
Body	0.714 × 0.880 m ± 0.04	0.7142 × 0.8800
Collider	≤ 400	238

Falsifiers (same code on all three binaries)

Flag	Budget	Exit
default	—	0
--skip-decimate	LOD1 ratio	9
--stray-vert	loose verts	15
--lift-z / --short-staves	grounded / named staves	16
--float-head	head-croze	17
--round-band	hoop seat	18

Framing gate passed on 5.2.1 (fill y=0.822, margins ≥ 0.056). 3 inspection rounds.

wooden-bucket

Defects (round 1)

1. 12 box-segment rope bail with V-gaps, never entered the ear rings — joint-bail, clay
2. Ear cubes punched through the rim — joint-ear
3. Overlapping identical staves (STAVE_GAP=-0.08) — joint-stave, wire
4. Circular hoops on a 14-gon — joint-hoop-mid
5. Circular floor floating inside the polygonal hull — joint-bottom, rim-interior

Structural fixes

• 16 staves, chord-seated hoops, linear taper + 12 mm sin bulge
• Floor = inner stave polygon in a croze above a chime (--float-bottom)
• Ear plates on host_outer_r + plate_t/2, top below the rim; flat XY rings; round semicircle bail through the rings (--float-handle shrinks rx)
• bail_join is min nearest distance from ring verts to bail BVH

Hygiene (all three binaries)

Axis	Declared	Measured
Base tris	4000–5800	4872 / 4872 / 4872 (was 4272)
Hygiene 15	0	0
zmin / 16 staves	16	0.0000 / 16
Bail-ear gap	≤ 0.006 m	0.00125
Floor-croze gap	≤ 0.008 m	0.00458
Hoop bite	0.0010–0.007 m	0.00250
Body	0.335 × 0.360 m ± 0.04	0.3349 × 0.3600
Collider	≤ 420	302

Falsifiers (same code on all three)

Flag	Budget	Exit
default	—	0
--skip-decimate	LOD1	9
--stray-vert	loose verts	15
--lift-z / --short-staves	grounded / named staves	16
--float-handle / --float-bottom	bail-ear / floor-croze	17
--round-band	hoop seat	18

Framing gate passed on 5.2.1 (fill y=0.733, margins ≥ 0.083). 3 inspection rounds.

Test plan

• blender-smoke 5.2 LTS and 4.5 LTS green on this head
• needs-5.1 labeled via REST; 5.1 smoke job appears and is green
• validate + drift-check + Socket
• Squash-merge with branch deletion, no --admin
• Post-merge: release tag, Pages, gallery 200

showcase/README.md conventions (hygiene 15–19, named supports, --round-band seat) were already in place — no convention commit.