feat: Add Windows build and run automation scripts (#8861)

* 🔧 (build_and_run.bat): Add a Windows batch script to build frontend, copy build files to backend, and run Langflow
🔧 (build_and_run.ps1): Add a Windows PowerShell script to build frontend, copy build files to backend, and run Langflow

* 📝 scripts/windows/build_and_run.bat: improve script messages for better clarity and consistency
📝 scripts/windows/build_and_run.ps1: update script steps numbering and messages for consistency and clarity

* 📝 (build_and_run.bat): Add attention message to wait for uvicorn to run before opening the browser
📝 (build_and_run.ps1): Add attention message to wait for uvicorn to run before opening the browser

scripts/windows/build_and_run.bat

@@ -0,0 +1,84 @@
+@echo off
+echo Starting Langflow build and run process...
+
+echo.
+echo Step 1: Installing frontend dependencies...
+cd ..\..\src\frontend
+if errorlevel 1 (
+    echo Error: Could not navigate to src\frontend directory
+    pause
+    exit /b 1
+)
+
+echo Running npm install...
+call npm install
+if errorlevel 1 (
+    echo Error: npm install failed
+    pause
+    exit /b 1
+)
+
+echo.
+echo Step 2: Building frontend...
+echo Running npm run build...
+call npm run build
+if errorlevel 1 (
+    echo Error: npm run build failed
+    pause
+    exit /b 1
+)
+
+echo.
+echo Step 3: Copying build files to backend...
+cd ..\..
+
+REM Check if build directory exists
+if not exist "src\frontend\build" (
+    if not exist "src\frontend\dist" (
+        echo Error: Neither build nor dist directory found in src\frontend
+        pause
+        exit /b 1
+    )
+    set BUILD_DIR=src\frontend\dist
+) else (
+    set BUILD_DIR=src\frontend\build
+)
+
+echo Copying from %BUILD_DIR% to src\backend\base\langflow\frontend\
+REM Create target directory if it doesn't exist
+if not exist "src\backend\base\langflow\frontend" (
+    mkdir "src\backend\base\langflow\frontend"
+)
+
+REM Remove existing files in target directory (FORCES CLEAN REPLACEMENT)
+echo Removing existing files from target directory...
+if exist "src\backend\base\langflow\frontend\*" (
+    del /q /s "src\backend\base\langflow\frontend\*"
+    for /d %%d in ("src\backend\base\langflow\frontend\*") do rmdir /s /q "%%d"
+)
+
+REM Copy all files from build directory
+xcopy "%BUILD_DIR%\*" "src\backend\base\langflow\frontend\" /e /i /y
+if errorlevel 1 (
+    echo Error: Failed to copy build files
+    pause
+    exit /b 1
+)
+
+echo Build files copied successfully!
+
+echo.
+echo Step 4: Running Langflow...
+echo.
+echo Attention: Wait until uvicorn is running before opening the browser
+echo.
+uv run langflow run
+if errorlevel 1 (
+    echo Error: Failed to run langflow
+    pause
+    exit /b 1
+)
+
+echo.
+echo Langflow build and run process completed!
+pause 

scripts/windows/build_and_run.ps1

@@ -0,0 +1,84 @@
+#!/usr/bin/env pwsh
+
+Write-Host "Starting Langflow build and run process..." -ForegroundColor Green
+
+# Step 1: Install frontend dependencies
+Write-Host "`nStep 1: Installing frontend dependencies..." -ForegroundColor Yellow
+try {
+    Set-Location "..\..\src\frontend"
+    Write-Host "Running npm install..."
+    npm install
+    if ($LASTEXITCODE -ne 0) {
+        throw "npm install failed"
+    }
+} catch {
+    Write-Host "Error in frontend dependency installation: $_" -ForegroundColor Red
+    Read-Host "Press Enter to exit"
+    exit 1
+}
+
+# Step 2: Build frontend
+Write-Host "`nStep 2: Building frontend..." -ForegroundColor Yellow
+try {
+    Write-Host "Running npm run build..."
+    npm run build
+    if ($LASTEXITCODE -ne 0) {
+        throw "npm run build failed"
+    }
+} catch {
+    Write-Host "Error in frontend build: $_" -ForegroundColor Red
+    Read-Host "Press Enter to exit"
+    exit 1
+}
+
+# Step 3: Copy build files
+Write-Host "`nStep 3: Copying build files to backend..." -ForegroundColor Yellow
+try {
+    Set-Location "..\.."
+    
+    # Determine build directory
+    $buildDir = if (Test-Path "src\frontend\build") {
+        "src\frontend\build"
+    } elseif (Test-Path "src\frontend\dist") {
+        "src\frontend\dist"
+    } else {
+        throw "Neither build nor dist directory found in src\frontend"
+    }
+    
+    $targetDir = "src\backend\base\langflow\frontend"
+    Write-Host "Copying from $buildDir to $targetDir"
+    
+    # Create target directory if it doesn't exist
+    if (-not (Test-Path $targetDir)) {
+        New-Item -Path $targetDir -ItemType Directory -Force | Out-Null
+    }
+    
+    # Remove existing files in target directory (FORCES CLEAN REPLACEMENT)
+    Write-Host "Removing existing files from target directory..." -ForegroundColor Cyan
+    if (Test-Path "$targetDir\*") {
+        Remove-Item "$targetDir\*" -Recurse -Force
+    }
+    
+    # Copy all files from build directory
+    Copy-Item "$buildDir\*" -Destination $targetDir -Recurse -Force
+    Write-Host "Build files copied successfully!" -ForegroundColor Green
+    
+} catch {
+    Write-Host "Error copying files: $_" -ForegroundColor Red
+    Read-Host "Press Enter to exit"
+    exit 1
+}
+
+# Step 4: Run Langflow
+Write-Host "`nStep 4: Running Langflow..." -ForegroundColor Yellow
+Write-Host "`nAttention: Wait until uvicorn is running before opening the browser" -ForegroundColor Red
+try {
+    uv run langflow run
+} catch {
+    Write-Host "Error running langflow: $_" -ForegroundColor Red
+    Read-Host "Press Enter to exit"
+    exit 1
+}
+
+Write-Host "`nLangflow build and run process completed!" -ForegroundColor Green
+Read-Host "Press Enter to exit"