Add isolated FFmpeg movie decoder shim

native/age_movie_ffmpeg/build-win64.ps1

@@ -0,0 +1,43 @@
+param(
+    [Parameter(Mandatory = $true)]
+    [string]$SdkRoot,
+    [string]$OutputDirectory
+)
+
+$ErrorActionPreference = 'Stop'
+$repoRoot = (Resolve-Path (Join-Path $PSScriptRoot '..\..')).Path
+$SdkRoot = (Resolve-Path $SdkRoot).Path
+if ([string]::IsNullOrWhiteSpace($OutputDirectory)) {
+    $OutputDirectory = Join-Path $repoRoot 'build\native\win-x64'
+}
+$include = Join-Path $SdkRoot 'include'
+$lib = Join-Path $SdkRoot 'lib'
+$bin = Join-Path $SdkRoot 'bin'
+foreach ($required in @(
+    (Join-Path $include 'libavformat\avformat.h'),
+    (Join-Path $lib 'avformat.lib'),
+    (Join-Path $bin 'avformat-62.dll')
+)) {
+    if (-not (Test-Path -LiteralPath $required)) { throw "Missing FFmpeg SDK file: $required" }
+}
+
+$vswhere = Join-Path ${env:ProgramFiles(x86)} 'Microsoft Visual Studio\Installer\vswhere.exe'
+if (-not (Test-Path -LiteralPath $vswhere)) { throw "Visual Studio Installer vswhere.exe was not found" }
+$vsInstall = & $vswhere -latest -products * -requires Microsoft.VisualStudio.Component.VC.Tools.x86.x64 -property installationPath
+if (-not $vsInstall) { throw "A Visual C++ x64 build environment was not found" }
+$vcvars = Join-Path $vsInstall 'VC\Auxiliary\Build\vcvars64.bat'
+if (-not (Test-Path -LiteralPath $vcvars)) { throw "Visual C++ x64 environment not found: $vcvars" }
+New-Item -ItemType Directory -Force -Path $OutputDirectory | Out-Null
+$source = Join-Path $PSScriptRoot 'age_movie.c'
+$object = Join-Path $OutputDirectory 'age_movie.obj'
+$dll = Join-Path $OutputDirectory 'age_movie_ffmpeg.dll'
+$importLibrary = Join-Path $OutputDirectory 'age_movie_ffmpeg.lib'
+$compile = 'call "{0}" && cl.exe /nologo /std:c11 /utf-8 /O2 /MD /W4 /external:I"{1}" /external:W0 /LD /Fo"{2}" "{3}" /link /OUT:"{4}" /IMPLIB:"{5}" /LIBPATH:"{6}" avformat.lib avcodec.lib avutil.lib swscale.lib' -f
+    $vcvars, $include, $object, $source, $dll, $importLibrary, $lib
+& cmd.exe /d /s /c $compile
+if ($LASTEXITCODE -ne 0) { throw "age_movie_ffmpeg compilation failed with exit code $LASTEXITCODE" }
+foreach ($runtime in @('avformat-62.dll', 'avcodec-62.dll', 'avutil-60.dll', 'swscale-9.dll', 'swresample-6.dll')) {
+    Copy-Item -LiteralPath (Join-Path $bin $runtime) -Destination $OutputDirectory -Force
+}
+Copy-Item -LiteralPath (Join-Path $SdkRoot 'LICENSE.txt') -Destination (Join-Path $OutputDirectory 'FFmpeg-LICENSE.txt') -Force
+Write-Output $dll