feat(desktop): embed BoosAPI Desktop client as a subproject

Vendor the rebranded BoosAPI Desktop client (Tauri + Vue) into metapi as
a monorepo subdirectory under desktop/. Source only — node_modules,
dist, Cargo target and the upstream .git history are excluded.

desktop/ keeps its own independent Cargo workspace (desktop/src-tauri
with crates/*); it is not part of the backend boosapi crate, so a
`cargo check` at the metapi root still compiles only the backend. Build
the desktop app from desktop/src-tauri per desktop/README.md.

Note: app icons are still placeholder assets pending the final BoosAPI
logo. The updater signing keys live outside the repo and are not
included.

desktop/src/test/setup.ts

@@ -0,0 +1,27 @@
+import '@testing-library/jest-dom';
+
+if (typeof window !== 'undefined' && !window.matchMedia) {
+  Object.defineProperty(window, 'matchMedia', {
+    writable: true,
+    value: (query: string) => ({
+      matches: false,
+      media: query,
+      onchange: null,
+      addListener: () => {},
+      removeListener: () => {},
+      addEventListener: () => {},
+      removeEventListener: () => {},
+      dispatchEvent: () => false,
+    }),
+  });
+}
+
+if (typeof globalThis.ResizeObserver === 'undefined') {
+  class ResizeObserver {
+    observe() {}
+    unobserve() {}
+    disconnect() {}
+  }
+
+  globalThis.ResizeObserver = ResizeObserver;
+}