feat: worker dashboard monorepo

- packages/cli: @uncaged/cli-dashboard (urec + uconn)
- packages/server: dashboard backend (port 3800)
- packages/frontend: React dark theme UI
- Normalized to bun monorepo conventions (TS, Biome, vitest, changesets, CI)

小橘 🍊（NEKO Team）

package.json

@@ -0,0 +1,10 @@
+{
+  "name": "worker-dashboard",
+  "private": true,
+  "workspaces": ["packages/*"],
+  "scripts": {
+    "dev:server": "node packages/server/src/index.mjs",
+    "dev:frontend": "npm -w @uncaged/dashboard-frontend run dev",
+    "build": "npm -w @uncaged/dashboard-frontend run build"
+  }
+}