Add devcontainer configuration for Julia development environment (#709)

* Initial plan

* Add devcontainer configuration with juliaup, Julia 1.10/1.12, hexdump, and HDF5 tools

Co-authored-by: JonasIsensee <[email protected]>

* Improve error handling in devcontainer setup script

Co-authored-by: JonasIsensee <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: JonasIsensee <[email protected]>

Author: Copilot

.devcontainer/README.md

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+# JLD2.jl Development Container
+
+This directory contains the development container configuration for GitHub Codespaces and VS Code Remote Containers.
+
+## What's Included
+
+### Julia Environment
+- **juliaup**: Julia version manager
+- **Julia 1.10 (LTS)**: Long-term support version
+- **Julia 1.12 (release)**: Latest stable release
+- Default channel set to 1.12
+
+### Development Tools
+- **hexdump**: Binary file analysis tool
+- **HDF5 CLI tools**: Complete suite of HDF5 utilities
+  - `h5dump`: Displays HDF5 file contents
+  - `h5debug`: HDF5 debugging tool
+  - `h5stat`: HDF5 file statistics
+  - `h5ls`: List HDF5 file contents
+  - `h5diff`: Compare HDF5 files
+  - Additional HDF5 utilities
+
+### VS Code Extensions
+- Julia Language Support
+
+## Usage
+
+### GitHub Codespaces
+When you create a new Codespace for this repository, the environment will be automatically configured with all the required tools.
+
+### VS Code Remote Containers
+1. Install the "Remote - Containers" extension in VS Code
+2. Open the repository in VS Code
+3. Click "Reopen in Container" when prompted (or use Command Palette: "Remote-Containers: Reopen in Container")
+
+## What Happens During Setup
+
+1. Base Ubuntu 22.04 container is created
+2. juliaup and Julia versions are installed via devcontainer feature
+3. The `setup.sh` script runs to:
+   - Install hexdump utility
+   - Install HDF5 CLI tools
+   - Verify all installations
+   - Install Julia package dependencies
+
+## Switching Julia Versions
+
+Use juliaup to switch between installed versions:
+
+```bash
+# List available versions
+juliaup list
+
+# Switch to Julia 1.10 (LTS)
+juliaup default 1.10
+
+# Switch to Julia 1.12 (release)
+juliaup default 1.12
+```
+
+## Verifying Installations
+
+All tools are verified during container creation. You can manually verify by running:
+
+```bash
+# Check Julia
+julia --version
+
+# Check hexdump
+hexdump --help
+
+# Check HDF5 tools
+h5dump --version
+which h5stat h5debug h5ls h5diff
+```

.devcontainer/devcontainer.json

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+{
+  "name": "JLD2.jl Development Environment",
+  "image": "mcr.microsoft.com/devcontainers/base:ubuntu-22.04",
+  
+  "features": {
+    "ghcr.io/devcontainers-contrib/features/juliaup:1": {
+      "channels": "1.10,1.12",
+      "defaultChannel": "1.12"
+    }
+  },
+
+  "postCreateCommand": ".devcontainer/setup.sh",
+
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "julialang.language-julia"
+      ],
+      "settings": {
+        "julia.environmentPath": "${workspaceFolder}"
+      }
+    }
+  },
+
+  "remoteUser": "vscode"
+}

.devcontainer/setup.sh

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+#!/bin/bash
+set -e
+
+echo "Setting up JLD2.jl development environment..."
+
+# Update package list
+sudo apt-get update
+
+# Install hexdump (part of bsdmainutils or bsdextrautils)
+echo "Installing hexdump..."
+sudo apt-get install -y bsdmainutils
+
+# Install HDF5 tools (h5dump, h5debug, h5stat, etc.)
+echo "Installing HDF5 CLI tools..."
+sudo apt-get install -y hdf5-tools
+
+# Verify installations
+echo "Verifying installations..."
+echo "Julia versions available:"
+juliaup list || echo "Julia installation pending..."
+
+echo "hexdump version:"
+hexdump -V 2>&1 || hexdump --version 2>&1 || echo "hexdump installed (no version flag available)"
+
+echo "HDF5 tools installed:"
+which h5dump && h5dump --version 2>&1 | head -n 1
+which h5stat && echo "h5stat: $(which h5stat)"
+which h5debug && echo "h5debug: $(which h5debug)"
+which h5ls && echo "h5ls: $(which h5ls)"
+which h5diff && echo "h5diff: $(which h5diff)"
+
+# Install Julia dependencies for the project
+echo "Installing Julia dependencies..."
+if julia --project=. -e 'using Pkg; Pkg.instantiate()'; then
+    echo "Julia dependencies installed successfully!"
+else
+    echo "Warning: Failed to install Julia dependencies."
+    echo "You may need to run 'julia --project=. -e \"using Pkg; Pkg.instantiate()\"' manually later."
+fi
+
+echo "Setup complete!"