[i18n] Adding Luganda structure

[fellyph]

This pull request adds Luganda (lg) translations for the documentation site, including navigation, sidebar, footer, and category labels, as well as a full translation of the coding standards documentation. These changes improve accessibility for Luganda-speaking users and ensure a consistent localized experience across the site.

Luganda localization of documentation site:

• Added Luganda translations for sidebar and category labels in current.json, covering Documentation, About Playground, Guides, Contributing, Blueprints, Tutorial, Steps, Developers, Local Development, Playground APIs, Javascript API, and Architecture.
• Added Luganda translations for footer labels, including Docs, Community, Documentation, Blueprints, Developers, API Reference, GitHub, Slack, copyright, and logo alt text in footer.json.
• Added Luganda translations for navbar items and logo alt text in navbar.json.
• Added Luganda category label for "Contributing" in _category_.json.

Documentation translation:

• Added a full Luganda translation of the coding standards documentation in coding-standards.md, including error message guidelines, public API principles, and blueprints best practices.

[adamziel]

Can we make this type of PRs an Agentic task to be started when someone wants to start translating to a new language?

[fellyph]

I can create one flow to create a structure.