feat: add compact mode for minimal widget interface (#36)

Add a compact mode that shrinks the window to a small widget showing
just the character sprite, recent messages, and a quick input box.
Perfect for quick questions while working without the full UI.

- Add CompactMode.svelte component with minimal widget interface
- Add compact mode toggle in StatusBar (Ctrl+Shift+M shortcut)
- Save/restore window size when toggling compact mode
- Handle display scaling by converting physical to logical pixels
- Add compact_mode to config (Rust + TypeScript)
- Add required Tauri window permissions for resize operations

src/lib/components/ConfigSidebar.svelte

@@ -29,6 +29,7 @@
     font_size: 14,
     streamer_mode: false,
     streamer_hide_paths: false,
+    compact_mode: false,
   });
 
   let isOpen = $state(false);