Add lattice QFT stub module

[Rahul-pamula]

This PR establishes a foundation for future lattice QFT work by adding a new top-level directory and stub, addressing the need for a starting point referencing external lattice QFT efforts.

Changes

• Physlib/LatticeQFT/Basic.lean (Added): Creates the foundation stub for lattice QFT, including comments referencing relevant external repositories as a starting point.
• Physlib.lean (Modified): Added the public import for Physlib.LatticeQFT.Basic to ensure the new directory is tracked by the project's build system and linters.

Reviewer Map

1. Review Physlib/LatticeQFT/Basic.lean to ensure the stub structure and comments accurately reflect the intention for future lattice QFT formalizations.
2. Review Physlib.lean to confirm the new module import is correctly placed and sorted.

[github-actions]

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[jstoobysmith]

We don’t really use “The Physlib Community” here. You’d be welcome to put your name if you want for the copyright and the author

[jstoobysmith]

Great, many thanks for fixing the author. Will merge this now. Thanks for the first PR.