Docs reader hardening

@beskid/docs-ui book and platform-spec reader shell refactor, unified nav drawer with persisted rail state, SpecPageHeader layout polish, YAML frontmatter quoting for MDX, Docker git for platform-spec git-meta prebuild, and nav client hardening across ClientRouter swaps.

Provenance

• Repository: beskid
• Commit: 278da1b
• Subject: fix(docs): unify doc nav drawer and persist rail state across navigation
• Closed: 2026-05-24

Catalog scope

• Delivery version: v0.3 (Macros, concurrency, and stabilization)
• Cutoff: f57377a→aaddd32 on superrepo beskid
• Workstreams: stabilization, dev-experience

Relation

Delivery anchor for 5 catalog task(s) in the v0.3 window; see linked workstreams and tasks with milestoneId / deliverableId v03-docs-reader-hardening.