Eliminates all std::any_cast usage across 41 files. Solution fields
are now accessed directly (e.g., solution.state_trajectory instead of
std::any_cast<vector<VectorXd>>(solution.at("state_trajectory"))).

Create cddp_example_utils.hpp with extractComponent, makeTimeVector,
ensurePlotDir, and makeInitialTrajectory helpers. Apply across all
examples to reduce boilerplate data extraction and directory setup.

- Skip convergence check after failed forward pass (prevents false
  convergence when dJ/dL are zero, which triggered LogDDP's abs check)
- Log unconditionally when ALL parallel forward pass threads fail
- Add checkEarlyConvergence hook so CLDDP checks inf_du before forward pass
- Record iteration history on early convergence path
- Fix BoxConstraint::computeViolation double-subtraction of ip_upper_bound_
- Add scale_factor_ to BoxConstraint<Control> control Jacobian for consistency
- Unify CDDPSolution::History and IterationHistory into single type
- Clean up solve() loop: remove continue, single printIteration call site

Both examples accessed solution.history.objective.back() but history
is only populated when return_iteration_info is enabled (default false).
Use solution.final_objective instead. Also fix ms-vs-microseconds label.

The template method hardcoded backward pass regularization exhaustion
to NotConverged. LogDDP originally treated this as Converged since the
barrier-penalized trajectory is typically still usable. Add virtual
handleBackwardPassRegularizationLimit hook with LogDDP override.

- Re-add throwing Hessian overrides for PoleConstraint and
  SecondOrderConeConstraint (nonlinear — zero Hessians are wrong)
- Keep zero-return default in base Constraint (correct for linear)
- Remove stale #include <any> from cddp_core.hpp
- Remove .claude/setting.json from tracked files