Remove deepcopy operations from __init path (fixes #747) (#763)

* Remove deepcopy operations from __init path

Fixes #747 by replacing deepcopy with copy for matrix A and vector b
in the initialization path. This allows trimming to work properly
for LinearSolve cases by avoiding the deepcopy operations that
prevented optimization.

The recent releases of SciMLOperators.jl now define proper copy
operations for SciMLOperators, making this change safe and effective.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

* Bump SciMLOperators requirement to v1.7.1

Updates the minimum SciMLOperators version to v1.7.1 which includes
the fix for FunctionOperator copy method handling of nothing values.
This resolves the CI failures by ensuring the copy operations work
correctly for all SciMLOperator types.

Related to SciMLOperators.jl PR #308

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

* Update Project.toml

---------

Co-authored-by: ChrisRackauckas <[email protected]>
Co-authored-by: Claude <[email protected]>

Author: 3 people

Project.toml

@@ -123,7 +123,7 @@ RecursiveFactorization = "0.2.23"
 Reexport = "1.2.2"
 SafeTestsets = "0.1"
 SciMLBase = "2.70"
-SciMLOperators = "1"
+SciMLOperators = "1.7.1"
 Setfield = "1.1.1"
 SparseArrays = "1.10"
 Sparspak = "0.3.9"

src/common.jl

@@ -321,7 +321,7 @@ function __init(prob::LinearProblem, alg::SciMLLinearSolveAlgorithm,
     elseif issparsematrixcsc(A)
         make_SparseMatrixCSC(A)
     else
-        deepcopy(A)
+        copy(A)
     end
 
     b = if issparsematrix(b) && !(A isa Diagonal)
@@ -334,7 +334,7 @@ function __init(prob::LinearProblem, alg::SciMLLinearSolveAlgorithm,
         # Extension must be loaded if issparsematrixcsc returns true
         make_SparseMatrixCSC(b)
     else
-        deepcopy(b)
+        copy(b)
     end
 
     u0_ = u0 !== nothing ? u0 : __init_u0_from_Ab(A, b)