UI redesign Phase 1: NavigationSplitView with collapsible sidebar

- Replace root VStack with NavigationSplitView (2-column, collapsible sidebar)
- Add SidebarView: new chat button, conversation search, list with swipe actions
- Slim HeaderView to text-only (provider + model + star); remove all icon rows
- Move status pills (Online, MCP, Synced) to footer right side
- Remove version number and shortcut hints from footer
- Add resizable InputBar with drag handle (persisted height) and globe/network.slash online toggle
- Fix Norwegian menu appearing on English systems (CFBundleLocalizations in Info.plist)
- Add View menu (Model Info, History, Stats, Credits, Online Mode toggle ⌘⇧O)
- Add ⌘L as alias for Search Conversations (muscle memory for /load users)
- Add Check for Updates to Help menu with download URL from Gitea API
- Add one-time Intel/Rosetta deprecation warning on first launch
- Swift 6: fix self.Self.isoString() call sites in DatabaseService

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

oAI/oAIApp.swift

@@ -92,6 +92,8 @@ struct oAIApp: App {
             CommandGroup(after: .newItem) {
                 Button("Open Chat…") { chatViewModel.showConversations = true }
                     .keyboardShortcut("o", modifiers: .command)
+                Button("Search Conversations") { chatViewModel.showConversations = true }
+                    .keyboardShortcut("l", modifiers: .command)
             }
 
             CommandGroup(replacing: .saveItem) {
@@ -113,10 +115,44 @@ struct oAIApp: App {
                 .disabled(chatViewModel.messages.filter { $0.role != .system }.isEmpty)
             }
 
+            // ── View menu ─────────────────────────────────────────────────
+            CommandMenu("View") {
+                Button("Select Model") { chatViewModel.showModelSelector = true }
+                    .keyboardShortcut("m", modifiers: .command)
+
+                Button("Model Info") {
+                    chatViewModel.modelInfoTarget = chatViewModel.selectedModel
+                }
+                .keyboardShortcut("i", modifiers: .command)
+                .disabled(chatViewModel.selectedModel == nil)
+
+                Divider()
+
+                Button("Command History") { chatViewModel.showHistory = true }
+                    .keyboardShortcut("h", modifiers: .command)
+
+                Button("In-App Help") { chatViewModel.showHelp = true }
+                    .keyboardShortcut("/", modifiers: .command)
+
+                Button("Credits") { chatViewModel.showCredits = true }
+
+                Divider()
+
+                Button(chatViewModel.onlineMode ? "Online Mode: On" : "Online Mode: Off") {
+                    chatViewModel.onlineMode.toggle()
+                }
+                .keyboardShortcut("o", modifiers: [.command, .shift])
+            }
+
             // ── Help menu ─────────────────────────────────────────────────
             CommandGroup(replacing: .help) {
                 Button("oAI Help") { openHelp() }
                     .keyboardShortcut("?", modifiers: .command)
+                Divider()
+                Button(UpdateCheckService.shared.isCheckingManually ? "Checking…" : "Check for Updates…") {
+                    UpdateCheckService.shared.checkForUpdatesManually()
+                }
+                .disabled(UpdateCheckService.shared.isCheckingManually)
             }
         }
         #endif