quantize-int8-smoothquant: use one fixed append-mode log file

Replace the per-run timestamped log filename with a single fixed
./quantize-int8-smoothquant.log opened in append mode, so successive runs
accumulate in one file. Drops the now-unused datetime import.

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

scripts/quantize-int8-smoothquant.py

@@ -86,7 +86,6 @@ import shutil
 import subprocess
 import sys
 import time
-from datetime import datetime
 from pathlib import Path
 
 import numpy as np
@@ -116,6 +115,7 @@ def configure_logging(log_file):
         str(log_file),
         level="DEBUG",
         format="{time:YYYY-MM-DD HH:mm:ss} | {level: <7} | {message}",
+        mode="a",  # append: one fixed file accumulates every run
         enqueue=True,
     )
     logger.info(f"[sq] logging to {log_file}")
@@ -391,13 +391,12 @@ def main():
                          "measured ~0.96 cosine yet tracked fp16 WER (10.9%% vs 10.2%%), so the "
                          "floor sits well below that. A true collapse lands far lower.")
     ap.add_argument("--ffmpeg", default=None, help="ffmpeg binary (else $FFMPEG / PATH)")
-    ap.add_argument("--log-file", default=None,
-                    help="path for the run log file (logs always also go to stderr). "
-                         "Default: ./quantize-int8-smoothquant-<timestamp>.log")
+    ap.add_argument("--log-file", default="quantize-int8-smoothquant.log",
+                    help="path for the run log file, appended to across runs (logs always "
+                         "also go to stderr). Default: ./quantize-int8-smoothquant.log")
     args = ap.parse_args()
 
-    log_file = args.log_file or f"quantize-int8-smoothquant-{datetime.now():%Y%m%d-%H%M%S}.log"
-    configure_logging(log_file)
+    configure_logging(args.log_file)
 
     model_dir = Path(args.model_dir)
     in_encoder = model_dir / "encoder-model.onnx"