Refactor so builder context only stores Blocks

[ducky64]

Having context be any Refable was overkill and didn't do anything except for one clone check, This changes builder context to only store Blocks (including Links), and has the context push happen in the init metaclass.

Other changes:

• Renames ConstraintExpr.parent to ConstraintExpr._context, since parent in Block and Port refer to a binding, whereas the Constraint binding is stored in the Binding object.
• Changes the __init__ hook to unconditionally pass through args and kwargs, instead of looking for *args, **kwargs.
• Prevents builder double-pushing the same context.
• Ensure the dummy instantiation of part libraries are in lambdas, otherwise they were being created on program start

[Copilot]

Pull Request Overview

This PR refactors the builder context mechanism to only store Block objects (including Link objects) instead of any Refable object. The builder context push is now handled in the init metaclass. This simplification removes unnecessary complexity while maintaining the same functionality.

Key changes:

• Builder context stack now only contains BaseBlock objects, simplifying the stack management
• The context push/pop mechanism is moved into the metaclass __init__ hooks for both Block and Link classes
• ConstraintExpr.parent is renamed to ConstraintExpr._context to better distinguish it from binding parent references

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
edg/core/Builder.py	Refactored Builder to only store BaseBlock in the stack; deprecated get_curr_context() in favor of get_enclosing_block()
edg/core/Core.py	Removed _lexical_parent and manual builder push from LibraryElement.__init__; ElementMeta now only sets _block_context
edg/core/HierarchyBlock.py	Modified BlockMeta to handle builder context push/pop in the metaclass wrapper and unconditionally pass through args/kwargs
edg/core/Link.py	Added LinkMeta metaclass to handle builder context push/pop for Link objects
edg/core/ConstraintExpr.py	Renamed parent field to _context for clarity
edg/core/Blocks.py	Updated references to use _block_context and improved error messages
edg/core/MultipackBlock.py	Updated to use renamed _context field
edg/core/Ports.py	Removed redundant _block_context field declaration
edg/parts/JlcFet.py	Wrapped lambda instantiation in tuple to ensure lazy evaluation
edg/jlcparts/JlcPartsFet.py	Wrapped lambda instantiation in tuple to ensure lazy evaluation
edg/jlcparts/JlcPartsDiode.py	Wrapped lambda instantiation in tuple to ensure lazy evaluation

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[Copilot]

Corrected spelling of 'unconditioally' to 'unconditionally'.

[Copilot]

The error message uses the deprecated get_curr_context() method instead of get_enclosing_block(). For consistency with the assertion condition and to use the non-deprecated API, this should be changed to builder.get_enclosing_block().

Suggested change

	assert builder.get_enclosing_block() is self._context, f"can't clone in original context {self._context} to different new context {builder.get_curr_context()}"
	assert builder.get_enclosing_block() is self._context, f"can't clone in original context {self._context} to different new context {builder.get_enclosing_block()}"