Fix HDF reading with new Cantera api

[erwanp]

• Implemented Cantera 3.1 transport names in ctwrap/modules/freeflame.py (no capitalization; soret uses multicomponent).
• Switched HDF I/O to Cantera’s native save/restore:
  • SolutionArray: save/restore via Cantera; loader uses instance .restore(fname, name=...).
  • FreeFlame: save/restore via Cantera.
• Updated docs/examples/freeflame_example.ipynb and docs/examples/ignition_example.ipynb to match new HDF layout (flame group for flames; data group for SolutionArray).
• Fixed Windows cleanup in tests/test_notebooks.py to avoid rm.
• Ensured invalid parallel test expects “unable to open file” by opening errored HDF as read-only.

Fixes #2