fix(showcase): give hover-bike pinned link-and-shock landing gear, aerofoil pylons and a panelled fuselage

Beside the other new-category pieces the hover bike was among the weakest:
plain round tubes for skids, struts and booms, a blocky riser and clamp,
and a smooth fuselage with few panel details for its size. The concept and
its good parts (shrouds, rotors, saddle, nozzles) stay; the rest is rebuilt:

- landing gear: at each end of each pylon a twin-plate pressed link from a
  pylon lug to a skid lug, and an oleo shock (anodised barrel, preload
  collar, pleated boot, chrome rod) from a pylon clevis to the link's
  middle; all 16 joints a headed pin with a nut through two bosses and one
  eye, on mount pads engulfing the pylon's trailing edge
- skids: ski-section shoes (flat sole, domed crown, upturned tips) in the
  livery on replaceable wear strips, bolted anodised end caps, a row of
  strip bolts, two cross braces with collars
- pylons: aerofoil section, chord vertical in the downwash, flared into
  both shroud walls, fairing webs into the belly, a hex-fastener row, a
  conduit in P-clips along the crest, the foot pegs
- fuselage: gasketed access panels (even 4 mm seam, corner fasteners), an
  alloy service plate on the belly, a decal plate, a hinged charge-port
  door with latch, a finned heat sink, a pillion grab rail, a tail-light
  cluster (red by object-space |y| between the nozzles)
- controls: twin chrome stanchions in boots through two sculpted triple
  clamps with pinch bolts, stem nut, fork caps, clip-on clamps, switch
  pods, levers on pivot bolts, a smaller cluster on a bracket under a
  small visor, a low fly screen
- materials: gunmetal and a new chrome carry the studio reflection term
  (after road-bicycle); the livery is muted to hold the saturation band

Coplanar hygiene fixed by staggering parts, not by widening bands: the
three bushings on a joint at three phases, twin plates and cheeks 0.4 mm
apart, hex heads turned 15 deg, skin/gasket/panel faces >= 1 mm apart.

Budget changes:
- Base tris 43700-45300 -> 45000-46000 (measured 45796; LOD 0.5000/0.2197)
- Materials 9 -> 10 (chrome), floors re-fitted; collider 1890 (ceiling
  2280 -> 1990, shroud lips 80 -> 72 segments)
- Outer AABB -> (2.234, 0.660, 1.112) m (the visor sets the top)
- Skids grounded now read the wear strips' soles (part-tagged faces)
- Stance margin 0.2599 -> 0.2515 (148.5 kg); shells 102 -> 322
- New: 16 joints, every bushing on its pin's axis (24, measured 0.000 mm);
  4 shocks, rod on the barrel's axis, 0.1233 m out of the gland (band
  0.100-0.140), 0.065 m engaged (floor 0.045) (25)

Falsifiers (flag -> measured -> exit), all on the final code:
  --skip-decimate  LOD1 1.0000                          9
  --stray-vert     loose_v 1                           15
  --lift-z         zmin 0.05000                        16
  --float-skid     y+ strip zmin 0.004                 16
  --offset-hub     hub 0.00250 m off axis              17
  --long-blades    clearance -0.00224 m                18
  --odd-hull       mirror 0.00799 m                    19
  --skew-blade     gap error 4.000 deg                 20
  --narrow-skids   margin 0.1715 m                     21
  --pop-lens       2 components                        22
  --offset-pin     bushing 0.001500 m off pin axis     24
  --skew-rod       rod 0.001500 m off barrel axis      25
  --short-rod      engaged 0.020 m                     25
--float-skid, --odd-hull and --pop-lens first stopped at hygiene (15);
the model was changed (the skid lug stays with the gear, the bow carries
everything laid on the skin, lens and housing both 32 segments half a step
apart), not the band. Every falsifier keeps the default AABB and tris.
tests/check_falsifier_targets.py --run --only hover-bike passes.

Evidence (live runs, local):
- .scratch/5.2/blender-5.2.1-windows-x64/blender.exe (Blender 5.2.1 LTS).
  Two default runs exit 0 with identical measured lines; hygiene all 0
  including coplanar cross-shell pairs.
- Framing: fill x 0.737, y 0.839; margins l .166 r .097 b .033 t .128.
- Contact sheet: luma 0.2417 (calibration 0.2369-0.2428), stage 0.2158,
  warmth -0.085, sat 0.2315 (band 0.1525-0.2367); before luma 0.2408,
  sat 0.2387 (over band).
- Asset sheet: before, a speeder on pipe skids and tube struts; now pinned
  links, orange shocks, teal skis, panelled flanks - clearly not the
  least-designed object in the lineup (the hydrant is simpler). Honest
  note: at thumbnail the gear is small; the shocks read as orange accents,
  the pins only up close.
- build_gallery, check_site_links and every tests/check_*.py pass.
- 4.5 LTS and 5.1 were not run locally.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: TMHSDigital

README.md

@@ -152,7 +152,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
   <a href="showcase/soccer-goal/"><img src="showcase/soccer-goal/preview.webp" width="24%" alt="Soccer goal: a white 5 by 2 m youth goal with sloped rear supports and a sagging diamond-mesh net edged in red rope, on a turf patch with a painted goal line, on a dark studio floor" /></a>
   <a href="showcase/fallen-log/"><img src="showcase/fallen-log/preview.webp" width="24%" alt="Fallen log: a mossy log settled into a soil mound, its dark furrowed bark peeled in patches, a hollow ringed butt, tiers of shelf fungi, toadstools, ferns and fallen leaves, on a dark studio floor" /></a>
   <a href="showcase/office-chair/"><img src="showcase/office-chair/preview.webp" width="24%" alt="Office chair: a graphite mesh-back task chair with a muted-teal two-tone seat, a mesh headrest and 4D armrests on a polished five-star base, standing on a smoked chair mat beside a snake plant in a stone planter" /></a>
-  <a href="showcase/hover-bike/"><img src="showcase/hover-bike/preview.webp" width="24%" alt="Hover bike: a teal sci-fi speeder with pearl racing stripes, a stitched black saddle, clip-on bars and two ducted fans with orange spinners, parked on landing skids, on a dark studio floor" /></a>
+  <a href="showcase/hover-bike/"><img src="showcase/hover-bike/preview.webp" width="24%" alt="Hover bike: a muted-teal sci-fi speeder with pearl racing stripes, panelled flanks, a stitched black saddle and two ducted fans with orange spinners, standing on pinned landing gear with orange shock absorbers and teal skis, on a dark studio floor" /></a>
   <a href="showcase/weight-rack/"><img src="showcase/weight-rack/preview.webp" width="24%" alt="Weight rack: a red half rack holding a barbell loaded with blue and yellow bumpers on J-hooks, plates on storage horns and two hex dumbbells, on a dark studio floor" /></a>
   <a href="showcase/boulder-cluster/"><img src="showcase/boulder-cluster/preview.webp" width="24%" alt="Boulder cluster: a speckled granite block, a banded sandstone boulder split in two and a slab resting on a smaller boulder, sunk in a grassy soil mound with pebbles and wildflowers, on a dark studio floor" /></a>
   <a href="showcase/floor-fan/"><img src="showcase/floor-fan/preview.webp" width="24%" alt="Floor fan: a sage-green 1950s pedestal fan with a chrome wire guard over four brass blades, its head turned on a tilt yoke, a telescoping column and a round cast base, its cord looped to a plug, on a dark studio floor" /></a>
@@ -253,7 +253,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
 
 [`office-chair`](showcase/office-chair/) — the second `household` piece: procedural ergonomic task chair on a chair mat at a desk corner (polished aluminium five-star base with ribbed spokes and five swivelled hooded twin-wheel casters, a chrome gas lift in a telescoping cover under a synchro-tilt mechanism with tension knob and paddles, a two-tone sculpted cushion with thigh channels, a waterfall front and piped welts in a moulded shell, an elastomeric mesh back and mesh headrest on graphite frames with an S-curved lumbar pad on sliders, 4D armrests, a smoked polycarbonate mat and a snake plant in a stone planter), whose mat flat on the floor with every wheel pressed into it, five-star spacing with plumb swivel stems on one circle, gas-lift column coaxial with hub and socket, mirrored level armrests with seat height and mass centre inside the caster contact hull, single connected chair, lumbar sliders clamped on the frame and leaves rooted in the soil are recomputed from the mesh, through the same pipeline. Falsifiers `--float-caster` and `--curl-mat` exit 16, `--skew-spoke` 17, `--offset-column` 18, `--uneven-arms` 19, `--loose-wheel` 20, `--float-lumbar` 21, `--float-leaves` 22.
 
-[`hover-bike`](showcase/hover-bike/) — the second `vehicles` piece: procedural sci-fi hover bike (a sculpted two-tone fuselage with panel seams, intake grilles, tail vents and cooling fins, a stitched pleated saddle, clip-on bars with grips, levers and an emissive instrument cluster, a flyscreen and headlight pod, two glowing exhaust nozzles, two ducted fans with canted stator vanes and handed seven-blade rotors, booms with foot pegs, and two landing skids on struts), whose skids on the floor, rotor hubs coaxial with their shrouds, blade-tip clearance to the shroud wall, mirror-symmetric fuselage with seat height, equal blade spacing, mass centre inside the skids' contact polygon and single connected assembly are recomputed from the mesh, through the same pipeline. Falsifiers `--float-skid` exits 16, `--offset-hub` 17, `--long-blades` 18, `--odd-hull` 19, `--skew-blade` 20, `--narrow-skids` 21, `--pop-lens` 22.
+[`hover-bike`](showcase/hover-bike/) — the second `vehicles` piece: procedural sci-fi hover bike (a sculpted two-tone fuselage with panel seams, gasketed access panels, a belly service plate, decal plate, charge-port door, heat sink, grab rail and tail light, a stitched pleated saddle, a twin-stanchion fork through sculpted triple clamps with clip-ons, switch pods, pivoted levers and a visored instrument cluster, two glowing exhaust nozzles, two ducted fans with canted stator vanes and handed seven-blade rotors, aerofoil pylons with fastener rows and a conduit, and landing gear of twin-plate pressed links and oleo shocks on 16 pinned joints carrying ski-section skids on wear strips), whose skids on the floor, rotor hubs coaxial with their shrouds, blade-tip clearance to the shroud wall, mirror-symmetric fuselage with seat height, equal blade spacing, mass centre inside the skids' contact polygon, single connected assembly, pins coaxial with their bushings and shock rods coaxial and inside their stroke band are recomputed from the mesh, through the same pipeline. Falsifiers `--float-skid` exits 16, `--offset-hub` 17, `--long-blades` 18, `--odd-hull` 19, `--skew-blade` 20, `--narrow-skids` 21, `--pop-lens` 22, `--offset-pin` 24, `--skew-rod` and `--short-rod` 25.
 
 [`weight-rack`](showcase/weight-rack/) — the third `sports` piece: procedural home-gym half rack (punched, numbered square uprights on bolted base plates and padded feet, side rails on bolted flanges, a pull-up bar, J-hooks with UHMW-lined saddles and spotter arms on pull pins, four plate-storage horns, an Olympic barbell with a knurled shaft, collars and sleeves loaded with 20 and 15 kg bumpers and 5 kg iron plates behind spring clips, and two hex dumbbells on the floor), whose pads and dumbbell heads on the floor, pull pins coaxial with their holes, bar seated in both saddles and level, plates coaxial and seated along their sleeves, balanced load and single connected rack are recomputed from the mesh, through the same pipeline. Falsifiers `--float-foot` exits 16, `--offset-pin` 17, `--float-bar` 18, `--hook-high` 19, `--gap-plate` 20, `--odd-load` 21, `--loose-horn` 22.