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/skills-lock.json

@@ -0,0 +1,15 @@
+{
+  "version": 1,
+  "skills": {
+    "nuxt-ui": {
+      "source": "nuxt/ui",
+      "sourceType": "github",
+      "computedHash": "9b7ff4c14185b7205c04c7ef41969d7b5c01e59c85e6d64083a7f497bf90b8d7"
+    },
+    "web-design-guidelines": {
+      "source": "vercel-labs/agent-skills",
+      "sourceType": "github",
+      "computedHash": "a6a44d5498f7e8f68289902f3dedfc6f38ae0cee1e96527c80724cf27f727c2a"
+    }
+  }
+}