Update web interface

run.bat

@@ -0,0 +1,50 @@
+@echo off
+setlocal enabledelayedexpansion
+cd /d "%~dp0"
+
+rem Force a UTF-8 console + UTF-8 mode in Python so prints with em-dashes and
+rem the like don't crash on machines whose console codepage is cp1252 / cp932.
+chcp 65001 >nul 2>nul
+set "PYTHONUTF8=1"
+set "PYTHONIOENCODING=utf-8"
+
+rem Pick a Python launcher. Try py first (works on most python.org installs),
+rem then `python`, then `python3`. enabledelayedexpansion + !ERRORLEVEL! is
+rem required so each check reads the value AFTER the preceding `where` runs.
+set "PYCMD="
+
+where py >nul 2>nul
+if !ERRORLEVEL! EQU 0 set "PYCMD=py"
+
+if not defined PYCMD (
+    where python >nul 2>nul
+    if !ERRORLEVEL! EQU 0 set "PYCMD=python"
+)
+
+if not defined PYCMD (
+    where python3 >nul 2>nul
+    if !ERRORLEVEL! EQU 0 set "PYCMD=python3"
+)
+
+if not defined PYCMD (
+    echo [run.bat] No Python found on PATH.
+    echo [run.bat] Install Python 3.10+ from https://www.python.org/downloads/
+    echo [run.bat] During install, tick "Add Python to PATH".
+    pause
+    exit /b 1
+)
+
+echo [run.bat] Using !PYCMD! to launch app.py.
+echo [run.bat] First run creates .venv and installs ~500 MB of packages.
+echo [run.bat] That can take several minutes; it only happens once.
+echo.
+
+!PYCMD! "%~dp0app.py" %*
+set "EXITCODE=!ERRORLEVEL!"
+
+if !EXITCODE! NEQ 0 (
+    echo.
+    echo [run.bat] app.py exited with code !EXITCODE!.
+    pause
+)
+endlocal & exit /b %EXITCODE%