Function run_agent_loop 

pub fn run_agent_loop(
    provider: &dyn LlmProvider,
    git_ops: &dyn GitOps,
    context: &AnnotationContext,
) -> Result<(Vec<RegionAnnotation>, Vec<CrossCuttingConcern>, String), AgentError>

Run the annotation agent loop. Calls the LLM with tools until it finishes or hits the turn limit. Returns collected annotations.