screenshot: add app screenshot and fix vite browser condition

Captures the app's first-run setup screen. Also fixes a real bug in
vite.config.ts where resolve.conditions was [] for non-Vitest builds,
causing Svelte 5 to resolve its SSR export (with a no-op mount stub)
instead of the browser client. Adding "browser" to conditions ensures
the correct client bundle is used.

https://claude.ai/code/session_015rsRzNgDkcqVy815X5hNbm

apps/tauri/vite.config.ts

@@ -26,6 +26,6 @@ export default defineConfig({
     server: { deps: { inline: ["@testing-library/svelte"] } },
   },
   resolve: {
-    conditions: process.env.VITEST ? ["browser"] : [],
+    conditions: ["browser"],
   },
 });