feat: Added devcontainer support

[BiosPlus]

Changes

Adds a dev container configuration for contributors using VS Code with either Docker or Podman.

The setup includes:

• A Dockerfile based on debian:bookworm-slim that installs Hugo Extended and Go at the minimum versions required by Lotus Docs (Hugo ≥ 0.140.0, Go ≥ 1.21.0)
• Architecture detection so the container builds correctly on both amd64 and arm64 machines (Intel/AMD and Apple Silicon)
• A non-root vscode user matching the devcontainer convention
• devcontainer.json configured to run hugo mod get on first create and start a Hugo server automatically on attach, with port 1313 forwarded

Tests

• Automated tests have been added
• This PR does not require tests

Changelog

• Entry has been added to changelog
• This PR does not make a user-facing change

Documentation

• Docs have been updated
• This change does not need a documentation update

Dark mode

• The UI has been tested both in dark and light mode
• This PR does not change the UI

[netlify]

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