feat(pl): add FORM pipeline support

[contagon]

Summary

• Add a new built-in FORM pipeline wrapper in evalio by adapting the reference binding from rpl-cmu/form main to the current evalio pipeline interface (add_lidar save-buffer semantics).
• Wire FORM into pipeline discovery/build by extending CMake registration and nanobind pipeline exports, including metadata and default parameter support.
• Extend pipeline setup tooling to clone rpl-cmu/form on main and apply a small compatibility patch that avoids hash specialization collisions with existing pipeline dependencies.
• Update API docs export list so FORM appears under evalio.pipelines reference docs.

Validation

• cmake -S . -B build -DEVALIO_BUILD_PYTHON=ON
• cmake --build build -j4
• Directly loaded built extension (build/cpp/bindings/_cpp.abi3.so) and confirmed FORM is exported from evalio._cpp.pipelines.