Reusable PC visor support — prototype 3 for R13 update 10

Print the corner, long rail and short rail in PC, feet down. The rails use
vertical tapered puzzle keys. Swap the two rails between corner legs for the
mirrored quarters: the long rail follows the printer's left/right dimension.
The same three parts are intended to serve all four quarter prints.

Full visor footprint plus 2 mm design padding. Measured perimeter margin
is at least 1.5 mm with ±0.2 mm placement play on all four quarters. Intentional sliding puzzle joints
leave narrow seams (checked within 0.11 mm of support); these are not
continuous contact surfaces.

Bare tool top: 14.44 mm. CAD visor underside: 14.50 mm. Bare gap: 0.06 mm.
Registration feet: approximately 0.20 mm nominal side clearance.
Puzzle keys: 0.10 mm radial clearance, tapering toward the bottom.

Use heavy glue stick on the support's top contact faces as the release coating.
Let it dry and check the coated height. A heavy coat may exceed the nominal
0.06 mm bare gap; do not assume the coated tool still has that clearance.
Keep glue off the locating feet and puzzle joints.

Use the maintained PC profile for the tool and PET-GF15 profile for the frame.
Before slicing the full frame, print the small matching coupon pair, then use
the PC coupon repeatedly to check release and surface wear. Neither the tool
nor the coupon has been physically tested yet.

Placement sequence (CAD-checked, not yet a sliced printer routine):
1. Print the frame up to the planned insertion pause, before the visor begins.
2. Assemble the support. Lower it into the open centre about 12 mm inward on
   each axis from its final position (roughly 17 mm diagonally).
3. With its feet resting on the bed, slide it outward to register against the
   printed lower rim. There is a little clearance; don't wedge or force it.
4. Resume only after checking the actual toolhead and travel clearance.
5. After printing and cooling, slide the tool inward before lifting it out.

Do not lower it vertically in its final position: the low feet hit the LED
backing during that approach. The inward-then-slide route avoids this.

Final height and pause must be reconciled with the first supported layer's
ACTUAL sliced underside. A normal 0.20 mm layer is larger than the 0.06 mm gap.
The CAD height is a trial dimension, not a ready-to-use pause Z. No mid-print
homing, probing or local layer-height correction is included.

The archive contains three full-size PC parts and two optional test coupons.
PET-GF15 visor coupon = part being printed. PC support coupon = reusable tool.
All parts are millimetres, with their print datum at Z0. No G-code is included.