MachineContactMedium - Medium Machine Contact

Finding from a model check for the capacitive-encoder boards. John Lauer's rule for every board we make: each part shows its real manufacturer marking in 3D (and nothing else), on a model proven against its drawing.

1. Marking. MachineContactMedium is an Adom machined press-fit contact with no factory marking (this page's own MPN-MARKING.md says the etch is "not a claim about factory marking"). The board-facing slots point at the AI-etched copy: component.parts.step and model_3d_step = machinecontactmedium-mpn.step (an Adom.LaserEtch.MPN group of 22 glyph solids on the top rim), and the hero is machinecontactmedium-mpn.png. Under the rule, step / model_3d_step should be the unmarked MachineContactMedium.step (sha256 cba99139...19279; the capencoder project uses that file as lib/3d/MachineContactMedium.step).

2. README dimension vs STEP. The Dimensions table says "Head / flange OD approx 1.4 mm, source: STEP / silkscreen". The STEP is at most 0.874 mm across: planar sections from z = -1.65 to 0 give a tapered body growing from about 0.71 mm to 0.87 mm OD at the top (bounding box x and y +/-0.437 mm, z -1.65 to 0). The 1.4 mm figure may be the silkscreen ring rather than the part. Overall height 1.65 mm agrees with "approx 1.7 mm". Please check which is right against the Machine Pin Dimensions sheet.

3. No drawing on the page. The dimensions are said to come from the Adom "Machine Pin Dimensions" sheet and adom-tsci-library globals.ts, both private. Without the drawing on the page the model cannot be proven by overlay as the component rule asks. Could the relevant sheet (or a dimensioned drawing) be published here, so the STEP can be checked against it?