Add lab restream pipeline with pirate_drift logo and lib/env.sh.

Encode-once/fanout scripts, HLS output, and single overloadable env source.
Commits assets/pirate_drift.png as default watermark for cluster runs.

Co-authored-by: Cursor <cursoragent@cursor.com>

bin/switch-source.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+# Stop pipeline, optionally rotate source index, restart (v0 switch_quality.sh cleanup).
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+# shellcheck disable=SC1091
+source "${ROOT}/lib/common.sh"
+
+VARIANT="${1:-}"
+SRC="${SRC:-}"
+
+if [[ "${VARIANT}" == "stop" ]]; then
+  exec "${ROOT}/bin/stop.sh"
+fi
+
+case "${VARIANT}" in
+  blur|blurred) export FILTER_PROFILE=blurred ;;
+  nologo) export FILTER_PROFILE=nologo ;;
+  default|'') export FILTER_PROFILE=default ;;
+  encode-only|record)
+    export RUN_ENCODE_ONLY=1
+    ;;
+  [0-9]*)
+    SRC="${VARIANT}"
+    ;;
+esac
+
+if [[ -z "${SRC}" && -f "${ROOT}/.current_source" ]]; then
+  # rotate index in sources.list
+  if [[ -f "${SOURCES_LIST}" ]]; then
+    count="$(grep -vc '^[[:space:]]*#' "${SOURCES_LIST}" || true)"
+    cur=1
+    [[ -f "${ROOT}/.current_index" ]] && cur="$(cat "${ROOT}/.current_index")"
+    cur=$((cur + 1))
+    [[ "${count}" -gt 0 && "${cur}" -gt "${count}" ]] && cur=1
+    echo "${cur}" > "${ROOT}/.current_index"
+    SRC="${cur}"
+  fi
+fi
+
+SRC="${SRC:-1}"
+
+"${ROOT}/bin/stop.sh"
+sleep 1
+log "switch → source index ${SRC} profile ${FILTER_PROFILE}"
+if [[ -n "${RUN_ENCODE_ONLY:-}" || "${VARIANT}" == "encode-only" || "${VARIANT}" == "record" ]]; then
+  exec "${ROOT}/bin/run-encode-only.sh" "${SRC}"
+fi
+
+exec "${ROOT}/bin/run.sh" "${SRC}"