Fixup dev container (#29376)

* Fixup dev container

* Fix yarn installation command in bootstrap script

* Fast restart

.devcontainer/Dockerfile

@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/devcontainers/python:1-3.14
+FROM mcr.microsoft.com/devcontainers/python:3.14
 
 ENV \
   DEBIAN_FRONTEND=noninteractive \

script/bootstrap

@@ -16,6 +16,12 @@ if [[ -n "$DEVCONTAINER" ]]; then
         nvm install --reinstall-packages-from="$nodeCurrent" --default
         nvm uninstall "$nodeCurrent"
     fi
+
+    # install yarn if not already available
+    if ! command -v yarn &> /dev/null; then
+        npm install -g corepack
+        yes | yarn
+    fi
 fi
 
 if ! command -v yarn &> /dev/null; then