ci: add devcontainer settings

.devcontainer/Dockerfile

@@ -0,0 +1,16 @@
+# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.203.0/containers/typescript-node/.devcontainer/base.Dockerfile
+
+# [Choice] Node.js version (use -bullseye variants on local arm64/Apple Silicon): 16, 14, 12, 16-bullseye, 14-bullseye, 12-bullseye, 16-buster, 14-buster, 12-buster
+ARG VARIANT="16-bullseye"
+FROM mcr.microsoft.com/vscode/devcontainers/typescript-node:0-${VARIANT}
+
+# [Optional] Uncomment this section to install additional OS packages.
+# RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
+#     && apt-get -y install --no-install-recommends <your-package-list-here>
+
+# [Optional] Uncomment if you want to install an additional version of node using nvm
+# ARG EXTRA_NODE_VERSION=10
+# RUN su node -c "source /usr/local/share/nvm/nvm.sh && nvm install ${EXTRA_NODE_VERSION}"
+
+# [Optional] Uncomment if you want to install more global node packages
+# RUN su node -c "npm install -g <your-package-list -here>"

.devcontainer/devcontainer.json

@@ -0,0 +1,42 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
+// https://github.com/microsoft/vscode-dev-containers/tree/v0.203.0/containers/typescript-node
+{
+    "name": "Node.js & TypeScript",
+    "runArgs": ["--init"],
+    "build": {
+        "dockerfile": "Dockerfile",
+        // Update 'VARIANT' to pick a Node version: 16, 14, 12.
+        // Append -bullseye or -buster to pin to an OS version.
+        // Use -bullseye variants on local on arm64/Apple Silicon.
+        "args": {
+            "VARIANT": "16-bullseye"
+        }
+    },
+
+    // Set *default* container specific settings.json values on container create.
+    "settings": {
+        "editor.formatOnSave": true
+    },
+
+    // Add the IDs of extensions you want installed when the container is created.
+    "extensions": [
+        "dbaeumer.vscode-eslint",
+        "GitHub.copilot",
+        "esbenp.prettier-vscode",
+        "JohannesRudolph.file-ext-switcher",
+        "yzhang.markdown-all-in-one",
+        "streetsidesoftware.code-spell-checker",
+        "GitHub.vscode-pull-request-github",
+        "wayou.vscode-todo-highlight",
+        "Gruntfuggly.todo-tree"
+    ],
+
+    // Use 'forwardPorts' to make a list of ports inside the container available locally.
+    // "forwardPorts": [],
+
+    // Use 'postCreateCommand' to run commands after the container is created.
+    "postCreateCommand": "npm install",
+
+    // Comment out connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
+    "remoteUser": "node"
+}