fix: isolate local command input and clarify audit aggregation

docs/architecture.md

@@ -63,6 +63,10 @@ resources or an existing server. The local executor can run directly on a
 prepared remote machine; SSH dispatch, distributed leases, automatic planning,
 patch generation and Hub publication remain future work.
 
+Local executor commands are noninteractive and receive EOF on standard input.
+Supply their inputs through command arguments or files rather than the caller's
+input stream.
+
 ## Directory map
 
 ![Implemented modules mapped to directories](assets/modular-directory-map-en.svg)

docs/examples/skill-comparison/cases.json

@@ -3,7 +3,7 @@
     "id": "audit-threshold",
     "split": "holdout",
     "mode": "audit",
-    "request": "Audit the fixed input report using its contract.",
+    "request": "Audit the fixed input report using its contract. Compute the median of per-trial request means, including every request in each trial, and the percentage reduction relative to the baseline aggregate.",
     "contract": {"min_reduction_pct": 20},
     "evidence_scope": "http_fixed_workload",
     "baseline": {

src/inferrsi/infra/executors/local.py

@@ -48,6 +48,7 @@ def execute_command(command: tuple[str, ...], cwd: Path, trial_dir: Path, deadli
                     argv,
                     cwd=cwd,
                     env=environment,
+                    stdin=subprocess.DEVNULL,
                     stdout=stdout,
                     stderr=stderr,
                     shell=False,

tests/test_local_executor.py

@@ -0,0 +1,40 @@
+import json
+import os
+import subprocess
+import sys
+from pathlib import Path
+
+
+def test_local_executor_does_not_inherit_parent_stdin(tmp_path):
+    child = tmp_path / "child.py"
+    child.write_text(
+        "import sys\n"
+        "from pathlib import Path\n"
+        "Path('received.txt').write_bytes(sys.stdin.buffer.read())\n",
+        encoding="utf-8",
+    )
+    parent = tmp_path / "parent.py"
+    parent.write_text(
+        "import json\n"
+        "import sys\n"
+        "import time\n"
+        "from pathlib import Path\n"
+        "from inferrsi.infra.executors.local import execute_command\n"
+        "command = (sys.executable, str(Path(__file__).with_name('child.py')))\n"
+        "result = execute_command(command, Path.cwd(), Path('trial'), time.monotonic() + 30)\n"
+        "print(json.dumps({'status': result['status']}))\n",
+        encoding="utf-8",
+    )
+    environment = dict(os.environ, PYTHONPATH=str(Path(__file__).resolve().parents[1] / "src"))
+    completed = subprocess.run(
+        (sys.executable, str(parent)),
+        cwd=tmp_path,
+        env=environment,
+        input="Unexpected instructions from the caller's input stream.\n",
+        text=True,
+        capture_output=True,
+        check=True,
+        timeout=60,
+    )
+    assert json.loads(completed.stdout) == {"status": "completed"}
+    assert (tmp_path / "received.txt").read_bytes() == b""