[BUG] Initial solution ‘accepted’ index updated incorrectly in generate_initial() (Routing solver)

When at least one initial solution has a route count greater than target_vehicles_, the code assigns an incorrect value to next_injection. For simplicity, let me consider example with a single initial solution by inspecting the first injection iteration. However, the same indexing mismatch can occur with multiple initial solutions whenever the route-count filter’s while-loop is entered.
https://github.com/NVIDIA/cuopt/blob/c76c186124bfde26409d52f9d5377fdd423ae1d3/cpp/src/routing/diversity/diverse_solver.hpp#L863-L873

• At line 865, temp_pair.first is set from injection_info.solutions[0].
• Entering the while-loop at lines 868–871, temp_pair.first is reassigned (still to injection_info.solutions[0] in this example), but the iterator is incremented and, at the end, next_injection is set to 1.

As a result, later in the function:
https://github.com/NVIDIA/cuopt/blob/c76c186124bfde26409d52f9d5377fdd423ae1d3/cpp/src/routing/diversity/diverse_solver.hpp#L896-L900

• At line 897, the solver injects temp_pair.first (which still refers to solution index 0),
• But at line 900, it updates injection_info.accepted[next_injection++] using index 1.

This is incorrect and, when there is only one initial solution (n_sol == 1), it also causes an out-of-bounds write.

Additionally, at the end of the solve, you can get the acceptance flags for initial solutions with assignment_t::get_accepted() (see assignment.cu (L187–L191)). Due to the indexing mismatch described above, the injected solution can be evaluated and inserted, yet the corresponding accepted entry (e.g., accepted[0]) may remain -1 (“not evaluated”) instead of 1 or 0 (“accepted” or "not accepted"). This is misleading for users and downstream tooling (including the Python API), since it suggests the initial solution wasn’t considered when it actually was.

I will create PR with fix.