Mobile feel: instant send, prepend anchoring, O(tail) streaming renders

apps/ios/ADE/App/ADEAppDelegate.swift

@@ -25,6 +25,18 @@ final class ADEAppDelegate: NSObject, UIApplicationDelegate {
         return true
     }
 
+    /// Transcript render caches (parsed Markdown blocks, inline attributed
+    /// strings, syntax highlighting) are all derived state — a long chat can
+    /// hold megabytes of it, and every entry can be rebuilt on demand. When the
+    /// system says it wants memory back, give it these first.
+    func applicationDidReceiveMemoryWarning(_ application: UIApplication) {
+        workPurgeMarkdownRenderCaches()
+        ADECodeRenderingCache.shared.purgeOnMemoryWarning()
+        MainActor.assumeIsolated {
+            WorkPendingUploadPreviewStore.shared.purge()
+        }
+    }
+
     /// Register the approval-alert category so approval pushes carry inline
     /// Approve / Deny actions on the lock screen and in Notification Center. The
     /// brain stamps `aps.category = "ADE_APPROVAL"` on those alerts; the action

apps/ios/ADE/Views/Components/ADECodeRenderingCache.swift

@@ -8,6 +8,10 @@ final class ADECodeRenderingCache {
   private let attributedCache = NSCache<NSString, AttributedStringBox>()
   private let regexCache = NSCache<NSString, NSRegularExpression>()
   private let regexLock = NSLock()
+  /// Streaming state, not a cache: one in-progress code block per language.
+  /// Guarded by its own lock because highlighting is reachable from any actor.
+  private let prefixLock = NSLock()
+  private var highlightPrefixes: [FilesLanguage: SyntaxHighlightPrefix] = [:]
 
   private init() {
     tokenCache.countLimit = 64
@@ -31,6 +35,28 @@ final class ADECodeRenderingCache {
     attributedCache.setObject(AttributedStringBox(value: attributed), forKey: key as NSString)
   }
 
+  func highlightPrefix(for language: FilesLanguage) -> SyntaxHighlightPrefix? {
+    prefixLock.lock()
+    defer { prefixLock.unlock() }
+    return highlightPrefixes[language]
+  }
+
+  func storeHighlightPrefix(_ prefix: SyntaxHighlightPrefix, for language: FilesLanguage) {
+    prefixLock.lock()
+    defer { prefixLock.unlock() }
+    highlightPrefixes[language] = prefix
+  }
+
+  /// Drops derived renders. Compiled regexes are cheap to hold and hot on every
+  /// highlight, so they stay.
+  func purgeOnMemoryWarning() {
+    tokenCache.removeAllObjects()
+    attributedCache.removeAllObjects()
+    prefixLock.lock()
+    highlightPrefixes.removeAll()
+    prefixLock.unlock()
+  }
+
   func regex(for pattern: String) -> NSRegularExpression? {
     let key = pattern as NSString
     if let cached = regexCache.object(forKey: key) {