Add canonical AzureLocal repository index with repo purpose, GitHub links, and docs links

[kristopherjturner]

Problem

We need a single canonical document in AzureLocal/platform that lists every repository in the AzureLocal org and explains what it is for.

Right now the repo inventory is fragmented and incomplete. Some repos are listed in the org profile, but we do not have one maintained source of truth that tells contributors:

• every repo in the org
• the purpose of each repo
• the GitHub repo link
• whether the repo publishes docs
• if docs exist, the public web/docs URL

Requested change

Add a README section or a dedicated document in platform that serves as the canonical AzureLocal repo index.

For each repository in the org, include:

• repository name
• short purpose/description
• GitHub repository URL
• whether it has MkDocs or other published docs
• public docs/site URL when available

Suggested output format

A table is probably the easiest format to maintain, for example:

Repo	Purpose	GitHub	Docs	Docs URL

Acceptance criteria

• All AzureLocal org repos are listed.
• Each repo has a short plain-language purpose statement.
• Each repo links to its GitHub repository.
• Repos with MkDocs or another published docs site include the public docs URL.
• Repos without published docs are clearly marked.
• The document is easy to discover from the main README or docs navigation.
• The location is treated as the canonical source of truth and can be kept current as repos are added.

Notes

A good follow-up would be to decide whether this should live in:

• README.md in platform
• a dedicated docs page in the platform docs site
• both, with one source and one pointer

It may also be worth defining a lightweight maintenance process so new repos must add/update their entry when they are created.