docs: preserve specification 0040 rebuild snapshot

[bordumb]

What changed

• preserves the current specification 0040 documentation-platform implementation
• replaces the earlier route/content graph with the source-backed MDX and product-snapshot architecture
• includes generated Markdown surfaces, shared documentation components, and site-audit tooling

Why

This is a preservation PR before beginning a new documentation direction. It is intentionally a draft and is not an endorsement of the current editorial result.

Checks

Not run for this handoff, per request.