feat(agent): add strategy quality introspection

Log full strategy JSON at debug level, show full anyhow cause chain on
submit failures, surface condition_audit_summary for 0-trade results in
both logs and the summary fed back to the AI each iteration.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/swym.rs

@@ -82,7 +82,7 @@ impl BacktestResult {
                 self.error_message.as_deref().unwrap_or("unknown error")
             );
         }
-        format!(
+        let mut s = format!(
             "[{}] trades={} win_rate={:.1}% pf={:.2} net_pnl={:.2} sharpe={:.2} avg_bars={:.1}",
             self.instrument,
             self.total_positions.unwrap_or(0),
@@ -91,7 +91,17 @@ impl BacktestResult {
             self.net_pnl.unwrap_or(0.0),
             self.sharpe_ratio.unwrap_or(0.0),
             self.avg_bars_in_trade.unwrap_or(0.0),
-        )
+        );
+        if self.total_positions.unwrap_or(0) == 0 {
+            if let Some(audit) = &self.condition_audit_summary {
+                let audit_str = format_audit_summary(audit);
+                if !audit_str.is_empty() {
+                    s.push_str(" | audit: ");
+                    s.push_str(&audit_str);
+                }
+            }
+        }
+        s
     }
 
     /// Is this result promising enough to warrant out-of-sample validation?
@@ -103,6 +113,35 @@ impl BacktestResult {
     }
 }
 
+/// Render a condition_audit_summary Value into a compact one-line string.
+/// Handles both object and array shapes we might receive from the API.
+fn format_audit_summary(audit: &Value) -> String {
+    match audit {
+        Value::Object(map) => map
+            .iter()
+            .map(|(k, v)| format!("{k}={v}"))
+            .collect::<Vec<_>>()
+            .join(", "),
+        Value::Array(arr) => arr
+            .iter()
+            .filter_map(|item| {
+                let name = item.get("name").or_else(|| item.get("condition"))?.as_str()?;
+                // Try common field names for hit counts
+                if let (Some(true_count), Some(total)) = (
+                    item.get("true_count").or_else(|| item.get("hit_count")).or_else(|| item.get("true_bars")).and_then(|v| v.as_u64()),
+                    item.get("total").or_else(|| item.get("total_bars")).or_else(|| item.get("evaluated")).and_then(|v| v.as_u64()),
+                ) {
+                    Some(format!("{name}: {true_count}/{total}"))
+                } else {
+                    Some(format!("{name}: {item}"))
+                }
+            })
+            .collect::<Vec<_>>()
+            .join(", "),
+        other => other.to_string(),
+    }
+}
+
 impl SwymClient {
     pub fn new(base_url: &str) -> Result<Self> {
         let client = Client::builder()