feat: `/props` endpoint

[eode]

Problem Statement

I'd like to be able to use this with tools like forge, but they require a functioning /props endpoint.

Proposed Solution

Implement the /props API endpoint as is done in llama.cpp and some others.

Documentation from llama.cpp:
GET props (as implemented by llama.cpp)
POST props (only if --props specified on cli for llama.cpp)

Alternatives Considered

n/a

Additional Context

No response