feat: wire list view models into AppModel, add strings, list helpers and debug snapshot mode

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Sources/Sst/main.swift

@@ -0,0 +1,12 @@
+import AppKit
+
+#if DEBUG
+// `Sst --snapshot <prefix>` renders the main window with sample data to <prefix>-transcripts.png and
+// <prefix>-dictionary.png (Aluminium left, Graphite right) and exits. No prompts, no model, no hotkey.
+if let flag = CommandLine.arguments.firstIndex(of: "--snapshot"), CommandLine.arguments.count > flag + 1 {
+    MainActor.assumeIsolated { Snapshot.run(prefix: CommandLine.arguments[flag + 1]) }
+    exit(0)
+}
+#endif
+
+SstApp.main()