Update control-free documentation with augment=true feature

- Explain augmented Hamiltonian approach for control-free problems
- Use CTFlows augment=true feature instead of manual H_aug construction
- Add mathematical formulation with transversality conditions
- Update both examples to match working scripts
- Remove @meta Draft block (use global draft setting)
- Use linestyle=:dash for better plot compatibility
- Clarify p_lambda(t0)=0 and p_omega(t0)=0 assumptions

Author: ocots