refactor(mesh): Remove duplicate Mesh constructor

Remove positional argument constructor that duplicated keyword constructor functionality. This eliminates method overwrite warning.

Kept only the keyword constructor which provides clearer API:
- mesh = Mesh{Hex8}(nodes, conn; element_sets=..., node_sets=...)

The keyword version is more explicit and prevents accidental parameter ordering mistakes.

src/mesh/mesh.jl

@@ -153,16 +153,6 @@ struct Mesh{N,T<:AbstractTopology{N}} <: AbstractMesh
 end
 
 # Positional constructor for convenience (backward compatibility)
-function Mesh{T}(
-    nodes::Vector{Vec{3,Float64}},
-    connectivity::Vector{NTuple{N,UInt32}},
-    element_sets::Dict{Symbol,Set{UInt32}}=Dict{Symbol,Set{UInt32}}(),
-    node_sets::Dict{Symbol,Set{UInt32}}=Dict{Symbol,Set{UInt32}}()
-) where {N,T<:AbstractTopology{N}}
-    Mesh{N,T}(nodes, connectivity, element_sets, node_sets)
-end
-
-# Keyword constructor for convenience
 function Mesh{T}(
     nodes::Vector{Vec{3,Float64}},
     connectivity::Vector{NTuple{N,UInt32}};