feat(free-router): run freellmapi under bun on localhost:9876 as a user service

dot_config/free-router/env

@@ -0,0 +1,4 @@
+# free-router settings: read by free-router.service (EnvironmentFile=) and
+# exported by fish, bash, and zsh. KEY=VALUE only; no quotes or expansion.
+FREE_ROUTER_PORT=9876
+FREE_ROUTER_API_KEY=sk_gz58b6RRX5