docs(openspec): add ADR-001 information architecture (#1701)

Codifies the 8-item top-level navigation (Registers, Schemas, Objects,
Integrations, Audit, Workflows, Beheer, API & Docs) and 5 placement rules
that keep new specs from inflating the menu. Distilled from the
cross-app information-architecture brief covering all 114 openregister
specs; sibling to the mydash ADR being authored in parallel.

Merge pull request #1594 from ConductionNL/hotfix/release

Formatted README

Merge pull request #1594 from ConductionNL/hotfix/release

Formatted README

Merge pull request #1594 from ConductionNL/hotfix/release

Formatted README

main branch overwritten with beta 2

main branch overwritten with beta 2

main branch overwritten with beta 2

main branch overwritten with beta 2

main branch overwritten with beta 2

main branch overwritten with beta 2