- nav: add functional mobile menu panel with JS toggle
- nav: hamburger now shows/hides mobile-menu with aria-expanded state
- about_page: full styled layout (header, prose body, author aside)
- legal_page: full styled layout (header with last-updated, max-w-3xl prose)
- article: fix aside newsletter label to 'Subscribe' for E2E test
- CSS: rebuild after all template changes (4.8KB → 24.3KB)
Committed CSS must match CI build — rebuilt after ALL template edits
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>