CLO-7: establish documentation architecture

[xdfuhub]

Summary

• add audience-based documentation, ADR, and plugin navigation
• record the QM documentation inventory, gaps, ownership, update triggers, and prioritized roadmap
• separate current QM behavior from the proposed Agent Squad Workspace extension and align planning terms with the accepted architecture baseline
• add lightweight ADR, feature specification, API/message protocol, runbook, test plan, and acceptance record templates
• remove an unresolved ADR-0003 reference from the Web UI guide

Verification

• npm exec --yes --package=prettier@3.9.1 -- prettier --check <affected Markdown files>
• relative repository link check across all affected Markdown files
• git diff --check
• node --test test/deploy-directory-doc.test.ts

The runtime provides Node 22.23.2 and npm 10.9.8, while this revision requires Node 24.18.0 and npm >=11.10.0. A full dependency install also encountered corrupted npm tarball retries, so the repository-wide npm run format:check wrapper could not be used. The exact locked Prettier version passed every affected file.

Closes CLO-7

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