Improve MCC testing workflow resilience

.skills/mcc-integration-testing/scripts/preflight_test_env.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+REPO_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
+# shellcheck source=tools/mcc-env.sh
+source "$REPO_ROOT/tools/mcc-env.sh"
+# shellcheck source=.skills/mcc-integration-testing/scripts/common.sh
+source "$SCRIPT_DIR/common.sh"
+
+usage() {
+    cat <<'EOF'
+Usage: preflight_test_env.sh [server-dir...]
+
+Checks the local MCC test environment and resolves common Java path issues.
+EOF
+}
+
+if [[ "${1:-}" == "-h" || "${1:-}" == "--help" ]]; then
+    usage
+    exit 0
+fi
+
+ensure_java_in_path
+command -v tmux >/dev/null 2>&1 || { echo "tmux was not found on PATH." >&2; exit 1; }
+command -v dotnet >/dev/null 2>&1 || { echo "dotnet was not found on PATH." >&2; exit 1; }
+command -v python3 >/dev/null 2>&1 || { echo "python3 was not found on PATH." >&2; exit 1; }
+
+if [[ ! -d "$MCC_SERVERS" ]]; then
+    echo "Server root not found: $MCC_SERVERS" >&2
+    exit 1
+fi
+
+for server_dir in "$@"; do
+    [[ -z "$server_dir" ]] && continue
+    if [[ ! -d "$MCC_SERVERS/$server_dir" ]]; then
+        echo "Server directory not found: $MCC_SERVERS/$server_dir" >&2
+        exit 1
+    fi
+
+    remove_stale_stdin_pipe "$server_dir"
+done
+
+printf 'MCC_REPO=%s\n' "$MCC_REPO"
+printf 'MCC_SERVERS=%s\n' "$MCC_SERVERS"
+printf 'JAVA=%s\n' "$(command -v java)"
+printf 'TMUX=%s\n' "$(command -v tmux)"
+printf 'DOTNET=%s\n' "$(command -v dotnet)"