Fix dimension mismatch in Rosenbrock solver when constraints are present

[Copilot]

When DAE constraints are enabled, variables_ has dimension state_size_ (species only) while temporary matrices (Ynew, K[], etc.) have dimension state_size_ + constraint_size_. Line 150 called Ynew.Copy(Y) which throws a runtime error on dimension mismatch.

Changes

• Replace Ynew.Copy(Y) at line 150 with manual element-wise copy of species variables only
• Use Ynew.NumRows() instead of Y.NumRows() in both copy loops for consistency with destination array

// Before: fails when constraint_size_ > 0
Ynew.Copy(Y);

// After: copy only species columns
Ynew.Fill(0.0);
for (std::size_t i_cell = 0; i_cell < Ynew.NumRows(); ++i_cell)
{
  for (std::size_t i_var = 0; i_var < state.state_size_; ++i_var)
  {
    Ynew[i_cell][i_var] = Y[i_cell][i_var];
  }
}

This mirrors the existing pattern at line 105-116 which already handled this correctly.

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.69%. Comparing base (b92f583) to head (1e0a03f).
⚠️ Report is 5 commits behind head on v2-review-dae-3-rosenbrock-integration.

Additional details and impacted files

@@                            Coverage Diff                             @@
##           v2-review-dae-3-rosenbrock-integration     #929      +/-   ##
==========================================================================
+ Coverage                                   94.66%   94.69%   +0.03%     
==========================================================================
  Files                                          68       68              
  Lines                                        3485     3241     -244     
==========================================================================
- Hits                                         3299     3069     -230     
+ Misses                                        186      172      -14     

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[K20shores]

I think the actual problem is that the temporary variables for the class are not properly sized. There is no reason Ynew and Y should ever have different sizes

[dwfncar]

Closing, superceded by #931