fix(runner): record wall-clock latency on error rows

An error row with zero latency reads as an instant rejection when it
can be three exhausted request timeouts. A 651-second thinking-model
generation looked instant in the 2026-08-30 run and misdirected the
diagnosis toward gateway rejection. The error path now records the
wall clock across all attempts.

config.example.yaml

@@ -5,7 +5,7 @@ models:
   - uni/qwen3.6-27b
   - uni/btl-4
 concurrency: 8         # default when omitted; matches internal/config's default
-request_timeout: 300s  # default when omitted
+request_timeout: 900s  # default when omitted
 max_tokens_default: 12000  # default when omitted; a reasoning model can spend
                             # thousands of tokens on reasoning_content before
                             # writing an answer, so this must stay generous

internal/runner/runner.go

@@ -161,9 +161,14 @@ func (r *Runner) runOne(ctx context.Context, model string, test testkit.Test) Re
 		Temperature: r.cfg.Temperature,
 	}
 
+	// Wall-clock across all attempts, recorded even on error: an error row
+	// with zero latency reads as an instant rejection when it may be three
+	// exhausted timeouts (a 651-second generation looked "instant" in the
+	// 2026-08-30 run and misdirected the diagnosis).
+	callStart := time.Now()
 	resp, err := r.client.Complete(ctx, req)
 	if err != nil {
-		return Result{Model: model, TestID: test.ID, Err: err}
+		return Result{Model: model, TestID: test.ID, Err: err, Latency: time.Since(callStart)}
 	}
 
 	normalized := testkit.Normalize(resp.Text)