feat: update maximum steps and token limits to usize::MAX; add split_spans_into_lines function for improved chat display

src/app/workflow/engine.rs

@@ -49,7 +49,7 @@ fn spawn_single_agent(prompt: &str, findings_snapshot: Vec<String>) -> anyhow::R
     use crate::app::subagent::spawn::AgentDefinition;
 
     let def = AgentDefinition::new("workflow-agent".to_string(), "coder".to_string())
-        .with_max_steps(20);
+        .with_max_steps(usize::MAX);
     let mut ctx = build_subagent_context(def);
 
     let findings_section = if findings_snapshot.is_empty() {