feat(metrics): C3 — Prometheus counters for L0/L1/format-loss/retry

routes/translate_routes.py

@@ -1418,12 +1418,43 @@ async def _run_translation_job(
                     min_chunks=getattr(config, "QUALITY_L1_MIN_CHUNKS", 10),
                     log_only=getattr(config, "QUALITY_L1_LOG_ONLY", True),
                 )
+
+                # When not in log-only mode, an L1 fail could trigger a
+                # retry. Record the intent (best-effort, never breaks job).
+                if (
+                    l1_result is not None
+                    and l1_result.verdict == "fail"
+                    and not getattr(config, "QUALITY_L1_LOG_ONLY", True)
+                ):
+                    try:
+                        from middleware.metrics import record_translation_retry
+                        record_translation_retry(
+                            reason="l1_fail",
+                            tier=_tier_for_quota(
+                                current_user.plan if current_user else None
+                            ) if current_user else "free",
+                        )
+                    except Exception:
+                        pass
             except Exception as l1_err:
                 # L1 must NEVER break a job. Log and continue.
                 logger.warning(
                     f"Job {job_id}: quality L1 layer failed: {l1_err}"
                 )
 
+        # Record L0 fail as a "potential retry" (also best-effort).
+        if l0_failed_indices and not getattr(config, "QUALITY_L1_LOG_ONLY", True):
+            try:
+                from middleware.metrics import record_translation_retry
+                record_translation_retry(
+                    reason="l0_fail",
+                    tier=_tier_for_quota(
+                        current_user.plan if current_user else None
+                    ) if current_user else "free",
+                )
+            except Exception:
+                pass
+
         if user_id:
             # Determine cost factor based on selected provider and model
             cost_factor = 1