Add devcontainer with Python 3.13 and uv support

Adds a Dockerfile-based development container using Microsoft's Python 3.13 image, with uv installed for dependency management.

Updates:
- Adds .devcontainer/Dockerfile based on Python 3.13
- Modifies devcontainer.json to use a local build
- Updates on-create-command.sh to install dependencies using uv

.devcontainer/Dockerfile

@@ -0,0 +1,9 @@
+# Base image: Match with .readthedocs.yaml and pyproject.toml
+FROM mcr.microsoft.com/devcontainers/python:3.13
+
+# Install uv and pre-commit globally
+RUN pip install --upgrade pip setuptools wheel uv pre-commit
+
+# Set workdir and default shell
+WORKDIR /workspaces/flask
+SHELL ["/bin/bash", "-c"]

.devcontainer/devcontainer.json

@@ -1,6 +1,8 @@
 {
   "name": "pallets/flask",
-  "image": "mcr.microsoft.com/devcontainers/python:3",
+  "build": {
+    "dockerfile": "Dockerfile"
+  },
   "customizations": {
     "vscode": {
       "settings": {

.devcontainer/on-create-command.sh

@@ -1,7 +1,15 @@
 #!/bin/bash
 set -e
+
+# Create a virtual environment and upgrade pip/setuptools/wheel
 python3 -m venv --upgrade-deps .venv
 . .venv/bin/activate
-pip install -r requirements/dev.txt
-pip install -e .
-pre-commit install --install-hooks
+
+# uv is already available (installed via Dockerfile). Use uv to install:
+# 1) the project in editable mode
+# 2) all dev dependencies (from pyproject.toml [project.optional-dependencies])
+uv pip install --editable . --group dev
+
+
+# Set up pre-commit hooks
+pre-commit install