By: Lucien Huber <im@lcnbr.ch>
move FeynKit workflows into native PyO3 API User requests: - There should be no Python facade functions; the API should all be PyO3 in FeynKit. - Emit valid Linnest code and render diagrams through typst-py. - Document all public classes, functions, methods, and meaningful accessors for particle physicists. - Remove empty Parameters blocks and trivial accessor examples. - Mark classes frozen where their public semantics are immutable.