Fix Rust feature install: use version stable so rustup is available for rust-analyzer

Co-authored-by: KSXGitHub <11488886+KSXGitHub@users.noreply.github.com>

Author: Copilot

.devcontainer/devcontainer.json

@@ -3,7 +3,7 @@
   "image": "mcr.microsoft.com/devcontainers/base:ubuntu-24.04",
   "features": {
     "ghcr.io/devcontainers/features/rust:1": {
-      "version": "none",
+      "version": "stable",
       "profile": "default"
     },
     "ghcr.io/devcontainers/features/node:1": {