feat: authorize iOS Hermes accounts and secure session isolation

Sources/App/SettingsStore.swift

@@ -8,9 +8,6 @@ final class SettingsStore: ObservableObject {
     @Published var voiceID: String {
         didSet { AppPreferences.store.set(voiceID, forKey: Keys.voiceID) }
     }
-    @Published var modelID: String? {
-        didSet { AppPreferences.store.set(modelID, forKey: Keys.modelID) }
-    }
     @Published var textMode: Bool {
         didSet { AppPreferences.store.set(textMode, forKey: Keys.textMode) }
     }
@@ -18,7 +15,6 @@ final class SettingsStore: ObservableObject {
     private enum Keys {
         static let serverURL = "serverURL"
         static let voiceID = "voiceID"
-        static let modelID = "modelID"
         static let textMode = "textMode"
     }
 
@@ -41,7 +37,6 @@ final class SettingsStore: ObservableObject {
         }
         let storedVoice = d.string(forKey: Keys.voiceID)
         voiceID = Voices.all.contains { $0.id == storedVoice } ? (storedVoice ?? "") : Voices.defaultID
-        modelID = d.string(forKey: Keys.modelID)
         textMode = d.bool(forKey: Keys.textMode)
     }
 
@@ -64,7 +59,6 @@ enum AppPreferences {
             if ProcessInfo.processInfo.arguments.contains("--live-testing") {
                 defaults.set(SettingsStore.defaultServerURL, forKey: "serverURL")
                 defaults.set(true, forKey: "textMode")
-                defaults.set("qwen2.5-vl-3b", forKey: "modelID")
             }
             return defaults
         }