Fig18 substrate: real output_length + criterion-A time_scale + Stop-A drain deadline

Replace the out=128 / scale=0.5 ablation substrate with a paper-faithful one:
- Use the trace's real output_length (drop completion_tokens_override=128). The
  0-8k chat window has p50=531 / p99=2436 / max=35168 output tokens, so decode
  (TPOT) becomes the dominant bottleneck instead of an artificial 128-token cap.
- replay_time_scale=0.8775, chosen by criterion-A: binary-search the smallest
  scale whose A-family L-C-A similarity to the real (scale=1.0) arrivals stays
  >= tau (0.90). The old scale=0.5 had sim_A=0.56, distorting the arrival axis
  far below the tau bar used everywhere else. New calibrator:
  scripts/calibrate_time_scale.py.
- Per-probe Stop-A-consistent drain deadline (worker._probe_drain_deadline): the
  wall-clock a *feasible* config needs to drain the LCA-admitted set
  (last_arrival + worst-case TTFT + p99_out * TPOT budget + margin). With real
  outputs decode dominates wall-clock, so the old fixed 320s cap would truncate
  the Stop-A offered window mid-decode. early_stop_max_elapsed_s (1000s) is now a
  hard ceiling; the per-probe deadline governs. The lag cap still cuts overload.

12-iter paired driver (both arms on dash1, removes the dash0/dash1 host confound):
scripts/run_ablation_pair_d1.sh. 115 tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

configs/examples/dash0_qwen27b_ablation_harness_on.json

@@ -130,9 +130,9 @@
       "min_input_tokens": 0,
       "max_input_tokens": 8192
     },
-    "replay_time_scale": 0.5,
+    "replay_time_scale": 0.8775,
     "early_stop_max_lag_s": 45.0,
-    "early_stop_max_elapsed_s": 320.0,
+    "early_stop_max_elapsed_s": 1000.0,
     "adaptive_stop": {
       "enabled": true,
       "tau": 0.9,
@@ -141,8 +141,7 @@
       "max_checks": 20,
       "min_fraction": 0.1,
       "boundary_delta": 0.02
-    },
-    "completion_tokens_override": 128
+    }
   },
   "slo": {
     "target_pass_rate": 0.95,

configs/examples/dash0_qwen27b_ablation_naive_off.json

@@ -130,9 +130,9 @@
       "min_input_tokens": 0,
       "max_input_tokens": 8192
     },
-    "replay_time_scale": 0.5,
+    "replay_time_scale": 0.8775,
     "early_stop_max_lag_s": 45.0,
-    "early_stop_max_elapsed_s": 320.0,
+    "early_stop_max_elapsed_s": 1000.0,
     "adaptive_stop": {
       "enabled": true,
       "tau": 0.9,
@@ -141,8 +141,7 @@
       "max_checks": 20,
       "min_fraction": 0.1,
       "boundary_delta": 0.02
-    },
-    "completion_tokens_override": 128
+    }
   },
   "slo": {
     "target_pass_rate": 0.95,