v0.32.9: nemotron_h: support the Nemotron 3.5 prompt layout

Select the 3.5 parser and renderer from its checkpoint template, preserve its prompt semantics, and map medium reasoning effort to the final-user annotation expected by the reference template.

Exercise parser and renderer registration, create-time metadata inference, and exact Jinja parity so created models cannot silently fall back to the Nemotron 3 renderer.