Move standards/*.mdx into docs/standards/ to consolidate under docs/

[kristopherjturner]

Problem

The platform repo currently has two `standards` locations with different purposes:

Path	Contents	Purpose
`/standards/`	11 `.mdx` source files + README	Canonical standards content — what the site syncs from, what product repo stubs link to
`/docs/standards/`	`consuming.md`, `contributing.md`, `authoring-guide.md`, `propagation.md`, stub `index.md`	Documentation about the standards system — how to consume, author, contribute

These are genuinely different things, but having a root-level `/standards/` alongside `/docs/` is inconsistent for a dedicated platform repo where everything else lives under `docs/`. A contributor landing on the repo sees two top-level standards locations and has to understand the distinction.

Proposed resolution

Move the 11 `.mdx` source files from `/standards/` into `/docs/standards/`, co-locating them with the how-to pages about the system.

The two sub-concerns could be separated:

• `docs/standards/` — index + how-to pages (consuming, contributing, authoring, propagation)
• `docs/standards/content/` — the actual `.mdx` source files

Or merged flat into `docs/standards/` if the how-to pages and the content pages can coexist cleanly in the same folder.

Downstream changes required

1. Sync workflow (azurelocal.github.io/.github/workflows/sync-standards.yml) — update the `find` path from `_platform/standards` to `_platform/docs/standards/content` (or wherever the content lands).
2. 6 product repo `STANDARDS.md` stubs — all link to `https://github.com/AzureLocal/platform/tree/main/standards\`; update to new path. Affected repos: `azurelocal-avd`, `azurelocal-sofs-fslogix`, `azurelocal-loadtools`, `azurelocal-vm-conversion-toolkit`, `azurelocal-copilot`, `azurelocal-nutanix-migration`.
3. `templates/_common/STANDARDS.md` — same URL, update the stub template.
4. ADR-0002 — references `platform/standards/` as the canonical path; update.
5. `standards/README.md` — becomes the `docs/standards/index.md` (merge or replace).
6. MkDocs nav in `mkdocs.yml` — currently references `standards/consuming.md` etc.; update to new path.

Timing note

This is the right time to do it. The 6 product-repo stubs were just merged in Phase 1 (2026-04-12) and no external documentation has been published pointing to the current `/standards/` path yet. Changing the path now costs one PR per affected repo; changing it after Phase 3 rollout (when all 13 repos have adopted it) costs significantly more.

Decision needed

• Agreed: move to `docs/standards/content/` (content separate from how-to pages)
• Agreed: merge flat into `docs/standards/` (simpler, content and how-to coexist)
• Rejected: keep `/standards/` at root — the external-link stability and sync simplicity outweigh the structural inconsistency

Once decided, execution is a single platform PR + 6 small stub-update PRs. Should be done before Phase 2 starts to avoid further baking in the current path.