Implement DIN rail mount feature

[bruceborrett]

Summary

Add a DIN rail mount option to generated enclosures so users can attach the enclosure to a standard DIN rail.

Desired behavior

• Add user-facing parameters for enabling/disabling DIN rail mounting.
• Support common DIN rail dimensions, starting with 35 mm top-hat rail compatibility.
• Generate mount geometry on the enclosure base/back side without interfering with screw posts, PCB mounts, holes, wall mounts, waterproof seals, or lid fit.
• Provide sensible defaults that work for typical electronics enclosures.
• Ensure the feature can be previewed in the renderer and included in exported geometry.

Implementation notes

• Keep the feature consistent with existing enclosure modules under src/app/core/enclosure/.
• Consider adding a dedicated DIN rail mount generator/module if the geometry is substantial.
• Expose the parameters through the existing params form/state flow.
• Include tests for parameter handling and geometry generation edge cases.

Acceptance criteria

• Users can enable a DIN rail mount from the app UI.
• Generated enclosures include a DIN rail-compatible mounting feature when enabled.
• The mount does not overlap existing optional features in common configurations.
• Existing enclosure generation behavior remains unchanged when the option is disabled.
• Unit tests cover the new feature and disabled/default behavior.

[bruceborrett]

@vZhurbenko thank you very much for the PR.

You implemented exactly what was described in the description, and the description made sense to me when I was initially thinking about this feature, but now, seeing it in action, I realise it is not very practical or optimal for 3D printing. The enclosure models are intended to be printed bottom down flat on the surface, the rail mount complicates that, adding the need for supports and making the print messy.

Im now wondering whether the rail mount should not perhaps be a separate part which the existing wall mounts can screw into, that makes parts clean and easy to print and also makes it possible to swap from wall mounted to DIN rail and vica versa.

[vZhurbenko]

@bruceborrett, thanks for the feedback.
Just to make sure I understand your suggestion correctly — are you proposing something like a separate DIN rail mounting plate that would attach to the existing wall mount "ears" (the same screw holes)? So the DIN mount becomes a separate part that screws into the enclosure using the existing mounting points, rather than being integrated into the main body.

[bruceborrett]

Yes, perhaps something like this:

[vZhurbenko]

WIP. Getting an STL and adapting it for the project =)