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/stream-monaco/.prettierrc.json

@@ -0,0 +1,22 @@
+{
+  "semi": false,
+  "tabWidth": 2,
+  "singleQuote": true,
+  "printWidth": 80,
+  "trailingComma": "all",
+  "overrides": [
+    {
+      "files": ["*.json5"],
+      "options": {
+        "singleQuote": false,
+        "quoteProps": "preserve"
+      }
+    },
+    {
+      "files": ["*.yml"],
+      "options": {
+        "singleQuote": false
+      }
+    }
+  ]
+}