feat(scrape): sync GUI bridge doc into linux-x64 folder

Add sync-gui-bridge-doc.sh to copy the versioned bridge markdown beside
the GUI zip; includes offline smoke test (18 total via run-all-smokes).

scripts/tests/sync-gui-bridge-doc-smoke.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+set -Eeuo pipefail
+
+REPO_ROOT=$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd -P)
+SYNC="$REPO_ROOT/scripts/sync-gui-bridge-doc.sh"
+TMP_DIR=$(mktemp -d "${TMPDIR:-/tmp}/dce-bridge-sync-smoke.XXXXXX")
+DEST="$TMP_DIR/gui-zip/RECURRING-SCRAPE.md"
+
+cleanup() {
+  rm -rf "$TMP_DIR"
+}
+trap cleanup EXIT
+
+mkdir -p "$TMP_DIR/gui-zip"
+
+"$SYNC" --dest "$DEST"
+[[ -f "$DEST" ]] || { printf 'ERROR: dest missing\n' >&2; exit 1; }
+grep -q 'operator-handoff' "$DEST" || { printf 'ERROR: dest content unexpected\n' >&2; exit 1; }
+
+printf 'sync-gui-bridge-doc-smoke: ok\n'