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/libs/markstream-vue/eslint.config.mjs

@@ -0,0 +1,28 @@
+import simon from '@antfu/eslint-config'
+
+export default simon(
+  {
+    ignores: [
+      '**/**/*.d.ts',
+      'test/fixtures/unclosed-fence.md',
+    ],
+  },
+  {
+    rules: {
+      'vue/no-v-for-template-key-on-child': 'off',
+      'no-console': 'off',
+      'ts/ban-types': 'off',
+      'jsdoc/require-returns-description': 'off',
+      'no-new-func': 'off',
+      'unicorn/no-new-array': 'off',
+      'jsdoc/require-returns-check': 'off',
+      'jsdoc/check-param-names': 'off',
+      'no-cond-assign': 'off',
+      'no-eval': 'off',
+      'antfu/no-import-dist': 'off',
+      'vue/require-toggle-inside-transition': 'off',
+    },
+    ignores: ['**/fixtures', 'test'],
+  },
+  {},
+)