feat: add review effort accounting and budget governor

pilot/observability/langfuse.py

@@ -249,6 +249,11 @@ def build_batch(
         tags.append(f"tier:{tier}")
     for lens in lenses or []:
         tags.append(f"lens:{lens}")
+    if usage.get("budget_cap_hit"):
+        tags.extend([
+            "budget:capped",
+            f"budget:{usage.get('budget_cap_reason', 'unknown')}",
+        ])
 
     costs, cost_basis = _cost_details(usage, model, price_target) if usage else ({}, "")
     if cost_basis:
@@ -267,7 +272,19 @@ def build_batch(
         "severities": _severity_counts(findings),
         "provider_cost_usd": usage.get("cost"),
         "cost_basis": cost_basis or None,
+        "iterations": usage.get("steps"),
+        "tool_calls": usage.get("tool_calls"),
+        "cap_hit": usage.get("budget_cap_hit"),
+        "cap_reason": usage.get("budget_cap_reason"),
+        "tokens_per_finding": round(
+            float(usage.get("total") or 0) / max(1, len(findings or [])), 2
+        ),
+        "steps_per_finding": round(
+            float(usage.get("steps") or 0) / max(1, len(findings or [])), 2
+        ),
     }
+    if usage.get("iterations"):
+        metadata["iteration_usage"] = usage["iterations"][:50]
     if lenses:
         metadata["lenses"] = lenses
     if tier: