Function initialize_decision 

pub fn initialize_decision(
    llm_settings: &Option<LlmSettings>,
    peer_sampling_supported: bool,
) -> InitializeDecision

v0.9.0 P2: decide the initialize outcome given the tenant’s [llm] config and whether the peer advertised the sampling capability.

Pure function — no side effects, no rmcp peer required. Pinned by initialize_decision_* tests.