Validate Pure quant for 256K Ultra profile

dev/run_qwen38_pure_256k.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+"""Focused 256K validation for the Qwen3.8 IQ4_XS-pure artifact.
+
+Reuses the synthetic dual-GPU runner. It reads no chats or user data, stops
+production inference for the isolated test and restores the Fast profile in
+the runner's finally block.
+"""
+
+from __future__ import annotations
+
+import importlib.util
+import pathlib
+import sys
+
+
+BASE = pathlib.Path("/opt/mike-ai/stack/run_qwen38_dualgpu_exhaustive.py")
+SPEC = importlib.util.spec_from_file_location("qwen38_dualgpu", BASE)
+if SPEC is None or SPEC.loader is None:
+    raise RuntimeError(f"Could not load {BASE}")
+
+runner = importlib.util.module_from_spec(SPEC)
+sys.modules[SPEC.name] = runner
+SPEC.loader.exec_module(runner)
+
+runner.OUT = pathlib.Path("/data/benchmarks/qwen38-pure-256k-20260822")
+runner.CASES = [
+    runner.Case(
+        "pure-262k-80-20-mtp2",
+        "iq4-pure",
+        262144,
+        (80, 20),
+        mtp=True,
+        mtp_max=2,
+        quality=False,
+        long_fill=0.84,
+    ),
+]
+
+raise SystemExit(runner.main())