Initial commit: scan_web integrated recording UI

FastAPI backend + vanilla JS frontend for LiDAR/camera startup, camera
settings, and rosbag recording, unifying the previous scan_gui/scan_gui_dual/
scan_gui_triple desktop tools into one web app.

open_scan_web.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+# Desktop-launcher entry point: starts the backend (if not already running)
+# and opens the browser once it's actually accepting requests, instead of a
+# blind sleep.
+set -euo pipefail
+
+URL="http://localhost:8000"
+LOG="/home/gardentech/scan_web_logs/server.log"
+mkdir -p "$(dirname "$LOG")"
+
+if ! curl -sf "$URL/api/status" >/dev/null 2>&1; then
+  nohup /home/gardentech/scan_web/run_scan_web.sh >>"$LOG" 2>&1 &
+  for _ in $(seq 1 60); do
+    if curl -sf "$URL/api/status" >/dev/null 2>&1; then
+      break
+    fi
+    sleep 0.5
+  done
+fi
+
+xdg-open "$URL" >/dev/null 2>&1 &