fix(qwen38): the calibration window must prove the rig owns the socket

The runner stops frank-archon first, and the dying production process keeps its
listener for a moment while the freshly created rig container is still loading.
'podman inspect says running' plus '/health answers' therefore BOTH hold for the
wrong process: measured 2026-10-30, the window logged 'health ok waited=0s',
the pusher refused on the container name, and a 12M window died at second zero.

The gate now asks the kernel who owns :7770 (ss -ltnp) and requires that pid to
be one of the rig container's processes (podman top). Two tests, written red
first against the old rig_up: a foreign listener must fail the window without a
push, and an in-container listener must proceed and bank.

Also renames the new test fixture to tap_window_fixture: it had shadowed the
existing window_fixture helper, which broke the window dry-run test when the
whole file ran.

scripts/qwen38-calib-window.sh

@@ -12,8 +12,13 @@
 # (2026-10-29) the rig's boot died of an OOM, the health loop quietly fell through, and the
 # pusher fed four rounds of 10M tokens into RESTORED PRODUCTION with nothing recorded:
 #
-#   1. the runner must still be alive and its container must answer /health, or this script
-#      kills it, restores the service and exits non-zero — no push, ever;
+#   1. the runner must still be alive and its container must answer /health AND own the
+#      listening socket, or this script kills it, restores the service and exits non-zero —
+#      no push, ever. The socket clause is not decoration: the runner stops frank-archon
+#      first, the dying process keeps its listener for a moment, and a rig container that
+#      is still loading has not bound the port yet, so `podman inspect` + `/health` both
+#      report success for the WRONG process (measured 2026-10-30: `health ok waited=0s`,
+#      then the pusher refused on the container name and the window died at second zero);
 #   2. the pusher refuses on its own unless the rig wrote its marker into the tap dir, the
 #      marker names this container, and the container is running (scripts/calib-push.py
 #      --tap-marker), so a second lock survives a mistake in this file;
@@ -79,8 +84,18 @@ say "phase=calib serve begin"
 bash scripts/run-qwen38-bf16.sh calib & spid=$!
 
 rig_up() {
-    podman inspect -f '{{.State.Running}}' "$RIG" 2>/dev/null | grep -qx true \
-        && curl -sf --max-time 10 -o /dev/null http://127.0.0.1:7770/health
+    podman inspect -f '{{.State.Running}}' "$RIG" 2>/dev/null | grep -qx true || return 1
+    curl -sf --max-time 10 -o /dev/null http://127.0.0.1:7770/health || return 1
+    # The answer must come from the CONTAINER. The runner stops frank-archon first, and the
+    # dying production process keeps its listener for a moment while the freshly created
+    # rig container is still loading — so `container running` + `/health` 200 both hold
+    # before the rig has bound anything. Measured 2026-10-30: `health ok waited=0s`, then the
+    # pusher refused on the container name and the window died at second zero. Ask the kernel
+    # who owns the listening socket and require it to be a rig process.
+    local lpid
+    lpid=$(ss -H -ltnp 'sport = :7770' 2>/dev/null | grep -o 'pid=[0-9]*' | head -1 | cut -d= -f2)
+    [ -n "${lpid:-}" ] || return 1
+    podman top "$RIG" pid 2>/dev/null | grep -qw "$lpid"
 }
 
 waited=0