Add DevContainer configuration (#131)

Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: William Easton <strawgate@users.noreply.github.com>

Author: strawgate

.devcontainer/devcontainer.json

@@ -0,0 +1,31 @@
+{
+  "name": "py-key-value",
+  "image": "ghcr.io/astral-sh/uv:python3.10-bookworm",
+  "features": {
+    "ghcr.io/devcontainers/features/node:1": {
+      "version": "lts"
+    }
+  },
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "ms-python.python",
+        "ms-python.vscode-pylance",
+        "charliermarsh.ruff",
+        "DavidAnson.vscode-markdownlint"
+      ],
+      "settings": {
+        "python.defaultInterpreterPath": "/usr/local/bin/python",
+        "python.testing.pytestEnabled": true,
+        "python.testing.unittestEnabled": false,
+        "python.testing.pytestArgs": [
+          "key-value",
+          "--import-mode=importlib",
+          "-vv"
+        ]
+      }
+    }
+  },
+  "postCreateCommand": "make sync",
+  "remoteUser": "root"
+}