Plate nesting GH components

[nbbosco]

This pull request introduces new Grasshopper components for plate stock definition and 2D plate nesting, and integrates nesting support into the BTLx export workflow. The changes enhance the fabrication toolset by enabling users to define plate stocks, perform automated nesting, and export nested results for downstream processes.

New Plate Stock and Nesting Components:

• Added the CT: PlateStocks component for defining raw plate material stocks, allowing users to specify stock dimensions and thicknesses. (src/timber_design/ghpython/components/CT_PlateStock/code.py, src/timber_design/ghpython/components/CT_PlateStock/metadata.json, [1] [2]
• Introduced the CT: NestPlates component, which performs 2D nesting of plates into defined stock sheets, outputs a NestingResult, and provides a summary including warnings if any issues occur. (src/timber_design/ghpython/components/CT_NestPlates/code.py, src/timber_design/ghpython/components/CT_NestPlates/metadata.json, [1] [2] [3]

Integration of Nesting into BTLx Export:

• Updated the CT_BTLx component to accept a nesting input parameter, enabling export of BTLx files based on the nesting result. (src/timber_design/ghpython/components/CT_BTLx/code.py, src/timber_design/ghpython/components/CT_BTLx/metadata.json, [1] [2] [3] [4]
• Increased the exposure level of the CT_BTLx component for greater visibility in the UI. (src/timber_design/ghpython/components/CT_BTLx/metadata.json, src/timber_design/ghpython/components/CT_BTLx/metadata.jsonL7-R7)

TO BE AWARE:

• Plate 2d nesting pull request still needs to be approved in Compas Timber repo to be implemented (Plate 2d nesting compas_timber#720).
• Icons used are WIP.

What type of change is this?

• Bug fix in a backwards-compatible manner.
• New feature in a backwards-compatible manner.
• Breaking change: bug fix or new feature that involve incompatible API changes.
• Other (e.g. doc update, configuration, etc)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• I added a line to the CHANGELOG.md file in the Unreleased section under the most fitting heading (e.g. Added, Changed, Removed).
• I ran all tests on my computer and it's all green (i.e. invoke test).
• I ran lint on my computer and there are no errors (i.e. invoke lint).
• I added new functions/classes and made them available on a second-level import, e.g. compas.datastructures.Mesh.
• I have added tests that prove my fix is effective or that my feature works.
• I have added necessary documentation (if appropriate)