Add devcontainer support

[ryan-steel]

Add devcontainer support

Problem

Manual setup required:

• Bazelisk, Python 3.x, Graphviz, C++ compiler
• Shell completion configuration
• IDE tooling setup

Adds friction to contributor onboarding. Platform variance between setups.

Solution

.devcontainer/ config (Dockerfile + devcontainer.json). Pre-installs all dependencies.

Matches upstream practice: https://eclipse-score.github.io/score/main/contribute/development/development_environment.html#devcontainer-setup

Use Cases

• Onboarding: Open in VS Code → "Reopen in Container" → build works
• Consistency: Same environment local and CI. No "works on my machine"
• IDE Integration: Provides tooling for IDE integration with compile-commands.json support built-in
• Cross-platform: Windows/Mac/Linux all get Linux environment
• Fork contributors: Reduces internal setup docs

Running

VS Code: Dev Containers extension → "Reopen in Container"