fix: use IPv4 for YouTube playback extraction

The default route returned a YouTube anti-bot challenge; the same bundled extractor and media URLs work over IPv4 without cookies. Limit the route choice to canonical YouTube videos so generic sites keep their existing routing.

Sources/App/YouTubeResolver.swift

@@ -245,7 +245,7 @@ enum YouTubeResolver {
         environment["PATH"] = directories.joined(separator: ":")
         let transport = "[protocol~='^(https?|m3u8(_native)?)$']"
         let resolution = height.map { "[height=\($0)]" } ?? "[height<=?1080]"
-        let arguments = [
+        var arguments = [
             "--ignore-config", "--no-plugin-dirs", "--no-cache-dir", "--no-remote-components",
             "--no-playlist", "--simulate", "--skip-download", "--dump-single-json",
             "--no-progress", "--color", "never", "--no-check-formats",
@@ -253,8 +253,12 @@ enum YouTubeResolver {
             "--socket-timeout", "20", "--extractor-retries", "0", "--retries", "0",
             "--format-sort", "res", "--format-sort-force",
             "--format", "bestvideo*[dynamic_range=?SDR]\(resolution)\(transport)+bestaudio\(transport)/best[dynamic_range=?SDR]\(resolution)\(transport)",
-            "--", webpageURL.absoluteString
         ]
+        if webpageURL.host == "www.youtube.com" {
+            arguments.append("--force-ipv4")
+        }
+        arguments.append("--")
+        arguments.append(webpageURL.absoluteString)
         let output = try await YouTubeExtraction(executable: executable, arguments: arguments, environment: environment).run()
         try Task.checkCancellation()
         if let error = dependencyError(String(decoding: output.stderr, as: UTF8.self).lowercased()) {