Add GitHub CLI and pre-commit hooks to devcontainer (zauberzeug#5741)

### Motivation

The devcontainer currently lacks GitHub CLI (`gh`) integration and
pre-commit hook setup, making it harder for contributors to interact
with GitHub (e.g., creating PRs, reviewing issues) and to catch
linting/formatting issues before pushing.

### Implementation

- **Dockerfile**: Added `gh` (GitHub CLI) to the installed packages.
- **devcontainer.json**:
- Added a persistent named volume (`gh-config`) mounted at
`~/.config/gh` so that `gh auth` tokens survive container rebuilds.
- Extended `postCreateCommand` to fix volume ownership, run `pre-commit
install`, and prompt for `gh auth login` if not already authenticated.
- **CONTRIBUTING.md**: Updated the devcontainer setup instructions to
note the GitHub authentication prompt on first launch.

### Progress

- [x] I chose a meaningful title that completes the sentence: "If
applied, this PR will..."
- [x] The implementation is complete.
- [x] If this PR addresses a security issue, it has been coordinated via
the [security
advisory](https://github.com/zauberzeug/nicegui/security/advisories/new)
process.
- [x] Pytests have been added (or are not necessary).
- [x] Documentation has been added (or is not necessary).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Falko Schindler <falko@zauberzeug.com>

Author: 3 people

.devcontainer/Dockerfile

@@ -5,7 +5,7 @@ ENV DEBIAN_FRONTEND=noninteractive \
 
 # Install packages
 RUN apt-get update && apt-get install --no-install-recommends -y \
-    sudo git chromium chromium-driver \
+    sudo git chromium chromium-driver gh \
     && rm -rf /var/lib/apt/lists/*
 
 # Install uv

.devcontainer/devcontainer.json

@@ -35,5 +35,12 @@
   },
   // More info: https://aka.ms/dev-containers-non-root.
   "remoteUser": "vscode",
-  "postCreateCommand": "uv sync"
+  "mounts": [
+    {
+      "source": "nicegui-gh-config",
+      "target": "/home/vscode/.config/gh",
+      "type": "volume"
+    }
+  ],
+  "postCreateCommand": "bash .devcontainer/post-create.sh"
 }

.devcontainer/post-create.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -e
+
+# Fix ownership of .config/gh (Docker volume mounts it as root)
+sudo chown vscode:vscode /home/vscode/.config
+sudo chown -R vscode:vscode /home/vscode/.config/gh
+
+uv sync
+uv run pre-commit install
+
+# Authenticate with GitHub CLI if not already logged in
+gh auth status >/dev/null 2>&1 || gh auth login -h github.com -p https -w || true

CONTRIBUTING.md

@@ -73,7 +73,7 @@ The simplest way to setup a fully functioning development environment is to star
 1. Ensure you have VS Code, Docker and the Dev Containers extension installed.
 2. Open the project root directory in VS Code.
 3. Press `F1`, type `Dev Containers: Open Folder in Container`, and hit enter (or use the bottom-left corner icon in VS Code to reopen in container).
-4. Wait until image has been build.
+4. Wait until the image has been built. (On first launch, watch the terminal for a GitHub authentication prompt.)
 5. Happy coding.
 
 ### Locally