Add Dockerfile and devcontainer.json for development environment setup

.devcontainer/Dockerfile

@@ -0,0 +1,28 @@
+FROM debian:bookworm-slim
+
+# Install core Linux development utilities
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    build-essential \
+    curl \
+    git \
+    ssh-client \
+    ca-certificates \
+    sudo \
+    gnupg \
+    procps \
+    unzip \
+    && rm -rf /var/lib/apt/lists/*
+
+# Create a non-root user 'vscode' with sudo privileges
+ARG USERNAME=vscode
+ARG USER_UID=1000
+ARG USER_GID=$USER_UID
+
+RUN groupadd --gid $USER_GID $USERNAME \
+    && useradd --uid $USER_UID --gid $USER_GID -m $USERNAME \
+    && echo $USERNAME ALL=\(ALL\) NOPASSWD:ALL > /etc/sudoers.d/$USERNAME \
+    && chmod 0440 /etc/sudoers.d/$USERNAME
+
+# Set the default user to the non-root user
+USER $USERNAME
+ENV HOME=/home/vscode

.devcontainer/devcontainer.json

@@ -0,0 +1,23 @@
+{
+  "name": "Generic Linux Dev Environment",
+  "build": {
+    "dockerfile": "Dockerfile"
+  },
+  "remoteUser": "vscode",
+  "updateRemoteUserUID": true,
+
+  "workspaceMount": "source=pi-hole-dev-vol,target=/workspace,type=volume",
+  "workspaceFolder": "/workspace",
+
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "vscode.git-base",
+        "vscode.git",
+        "mhutchie.git-graph",
+        "eamodio.gitlens"
+      ]
+    }
+  },
+  "overrideCommand": true
+}