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/probe-source.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+# ffprobe → normalized source profile (draft SPEC-1 preview).
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+# shellcheck disable=SC1091
+source "${ROOT}/lib/common.sh"
+# shellcheck disable=SC1091
+source "${ROOT}/lib/source.sh"
+
+resolve_source "${1:-}"
+require_cmd "${FFPROBE_BIN}"
+
+probe_target="${SOURCE_URL}"
+if [[ "${USE_YTDLP}" == "1" ]]; then
+  warn "page URL — ffprobe may fail; use a direct m3u8/mp4 URL or run encode-once"
+fi
+
+log "probing ${probe_target}"
+"${FFPROBE_BIN}" -hide_banner -loglevel error \
+  -show_format -show_streams -print_format json \
+  "${probe_target}" | python3 -c '
+import json, sys
+data = json.load(sys.stdin)
+fmt = data.get("format", {})
+streams = data.get("streams", [])
+v = next((s for s in streams if s.get("codec_type") == "video"), None)
+a = next((s for s in streams if s.get("codec_type") == "audio"), None)
+out = {
+    "duration": fmt.get("duration"),
+    "bitrate": fmt.get("bit_rate"),
+    "format": fmt.get("format_name"),
+    "video": None,
+    "audio": None,
+}
+if v:
+    out["video"] = {
+        "codec": v.get("codec_name"),
+        "width": v.get("width"),
+        "height": v.get("height"),
+        "fps": v.get("avg_frame_rate"),
+        "profile": v.get("profile"),
+    }
+if a:
+    out["audio"] = {
+        "codec": a.get("codec_name"),
+        "channels": a.get("channels"),
+        "sample_rate": a.get("sample_rate"),
+    }
+print(json.dumps(out, indent=2))
+'