Windows packaging: Start Menu/Add-Remove icon, no console window, correct description

The MSI Icon id had no .ico/.exe extension, which Windows Installer needs for
advertised shortcuts and ARPPRODUCTICON, so both showed a blank icon. Release
builds of the desktop app are now GUI-subsystem (no console window; the CLI stays
a console program), the shortcut/summary description names what VectorCraft does, and
packaging-lint rejects an Icon id without an extension. Found in printcraft#57.

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

apps/vectorcraft/src/main.rs

@@ -5,6 +5,7 @@
 //! `--control <port>` (or `VECTORCRAFT_CONTROL_PORT`) starts a localhost JSON-lines control server:
 //! `{"id":1,"method":"ui.inspect","params":{}}` → `{"id":1,"ok":true,"result":…}`.
 //! See `vectorcraft_ui_egui::control` for the methods.
+#![cfg_attr(all(target_os = "windows", not(debug_assertions)), windows_subsystem = "windows")]
 
 mod clipboard;
 mod control_server;