Add the Python extension and interpreter path to the devcontainer

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.devcontainer/devcontainer.json

@@ -19,5 +19,15 @@
     "postCreateCommand": "pip install -U pip && pip install -U -r requirements.txt -r requirements-dev.txt",
     "forwardPorts": [
         8757
-    ]
+    ],
+    "customizations": {
+        "vscode": {
+            "extensions": [
+                "ms-python.python"
+            ],
+            "settings": {
+                "python.defaultInterpreterPath": "/opt/venv/bin/python"
+            }
+        }
+    }
 }