fix usd metric

src/metrics.rs

@@ -35,8 +35,8 @@ pub fn task_failed(event_type: &str) {
         .increment(1);
 }
 
-pub fn openrouter_cost_usd(cost: u64) {
-    counter!("herald_openrouter_cost_usd_total").increment(cost);
+pub fn openrouter_cost_usd(cost: f64) {
+    counter!("herald_openrouter_cost_cents_total").increment((cost * 100.0).round() as u64);
 }
 
 pub fn describe() {
@@ -46,7 +46,7 @@ pub fn describe() {
     describe_gauge!("herald_bot_tasks_active", Unit::Count, "Bot tasks currently in progress");
     describe_counter!("herald_bot_tasks_completed_total", Unit::Count, "Bot tasks completed successfully");
     describe_counter!("herald_bot_tasks_failed_total", Unit::Count, "Bot tasks that failed");
-    describe_counter!("herald_openrouter_cost_usd_total", Unit::Count, "Total OpenRouter cost in USD");
+    describe_counter!("herald_openrouter_cost_cents_total", Unit::Count, "Total OpenRouter cost in cents (divide by 100 for USD)");
 }
 
 pub fn install(bind_addr: &str) -> anyhow::Result<()> {