完善跨平台回放与实时状态更新

start.ps1

@@ -0,0 +1,15 @@
+$ErrorActionPreference = "Stop"
+$Base = Split-Path -Parent $MyInvocation.MyCommand.Path
+
+Write-Host "[StreamCore] Starting backend..."
+$Python = Join-Path $Base "backend\.venv\Scripts\python.exe"
+if (-not (Test-Path $Python)) {
+    $Python = Join-Path $Base "backend\venv\Scripts\python.exe"
+}
+if (-not (Test-Path $Python)) {
+    throw "Python virtual environment not found. Create backend\.venv and install backend\requirements.txt."
+}
+
+Start-Process -FilePath $Python -ArgumentList "run.py" -WorkingDirectory (Join-Path $Base "backend")
+Write-Host "[StreamCore] Backend started on http://127.0.0.1:8080"
+Write-Host "Run npm install and npm run dev in frontend for the development UI."