* Accept OMP session state without thinkingLevel
Models whose reasoning effort is encoded in the model ID (e.g.
cursor-grok-4.5-high-fast) are marked reasoning: false by OMP, which
omits thinkingLevel from get_state. The required schema field made
session creation throw a ZodError. Make it optional and resolve the
thinking option to null when absent.
* Render OMP advisor messages as blocks
