feat(basis): Enable Lagrange{T,P} basis functions in main module

- Uncommented include for lagrange_generated.jl
- Added exports: AbstractBasis, Lagrange, Serendipity
- Updated comments to reflect new parametric architecture

Package now loads successfully with new basis system.
All 15 element types available:
  Lagrange{Segment, 1}, Lagrange{Segment, 2}
  Lagrange{Triangle, 1}, Lagrange{Triangle, 2}
  Lagrange{Quadrilateral, 1}, Lagrange{Quadrilateral, 2} (×2 variants)
  Lagrange{Tetrahedron, 1}, Lagrange{Tetrahedron, 2}
  Lagrange{Hexahedron, 1}, Lagrange{Hexahedron, 2} (×2 variants)
  Lagrange{Pyramid, 1}
  Lagrange{Wedge, 1}, Lagrange{Wedge, 2}

src/JuliaFEM.jl

@@ -205,12 +205,13 @@ include("basis/subs.jl")  # Symbolic substitution (includes minimal simplify fro
 include("basis/vandermonde.jl")
 
 # Lagrange basis functions - auto-generated file contains all basis types
-# Types have "Basis" suffix to avoid conflicts with topology types
-# E.g., Tri3Basis, Quad4Basis, etc. (not Tri3, Quad4 which are topology types)
+# Now generates methods for parametric Lagrange{T,P} type instead of separate types
 include("basis/lagrange_generator.jl")
-# OLD generated basis files - commented out during refactoring to new Lagrange{T,P} design
-# include("basis/lagrange_generated.jl")  # Auto-generated by scripts/generate_lagrange_basis.jl
-# TODO: Regenerate for new parametric Lagrange{T,P} architecture
+include("basis/lagrange_generated.jl")  # Auto-generated by: julia --project=. src/basis/lagrange_generator.jl
+
+# Export basis types and functions
+export AbstractBasis, Lagrange, Serendipity
+export nnodes, get_reference_element_coordinates, eval_basis!, eval_dbasis!
 
 include("basis/nurbs.jl")
 # OLD NURBS basis files - commented out during AbstractBasis refactoring