fix: remove WKProcessPool — iOS 15+ shares process automatically

API deprecated since iOS 15. All WKWebViews already share one
WebContent process. Our singleton WKWebView + shared config is
sufficient.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ios/Platform/Platform/Features/Reader/Views/ArticleWebView.swift

@@ -9,15 +9,8 @@ final class ArticleRenderer {
 
     let webView: WKWebView
 
-    // Explicit shared process pool — guarantees all WebViews share
-    // one WebContent process, even though iOS 15+ does this by default.
-    // Being explicit prevents accidental divergence if a second
-    // WKWebView is ever created elsewhere.
-    static let processPool = WKProcessPool()
-
     private init() {
         let config = WKWebViewConfiguration()
-        config.processPool = ArticleRenderer.processPool
         config.allowsInlineMediaPlayback = true
 
         webView = WKWebView(frame: .zero, configuration: config)