Light theme default + yt-dlp search fallback

INSTALLER_WINDOWS.ps1

@@ -0,0 +1,15 @@
+$ErrorActionPreference = "Stop"
+$ProjectRoot = Split-Path -Parent $MyInvocation.MyCommand.Path
+$Pubspec = Join-Path $ProjectRoot "pubspec.yaml"
+$Version = "1.0.0"
+if (Test-Path $Pubspec) {
+    $Text = Get-Content $Pubspec -Raw
+    if ($Text -match '(?m)^version:\s*([^\s+]+)(?:\+\S+)?\s*$') {
+        $Version = $Matches[1].Trim()
+    }
+}
+$Setup = Join-Path $ProjectRoot "dist\YouTube_Personal_Setup_$Version.exe"
+if (-not (Test-Path $Setup)) {
+    throw "Installateur introuvable : $Setup`nLance d'abord .\CREER_INSTALLATEUR_WINDOWS.ps1"
+}
+Start-Process -FilePath $Setup -Verb RunAs