Theme Bootstrap and Accessible Navigation Foundation
Selects the real four-period theme before blocking styles to avoid a needless day-wallpaper request, and adds a trilingual skip link, landmarks, and one H1 for the active route.
# Theme Bootstrap and Accessible Navigation Foundation
This release improves first-paint resources and page semantics so the correct four-period theme loads from the first frame and keyboard or assistive-technology users can reach the active content quickly.
## First-paint theme
- Before blocking styles load, an early bootstrap selects morning, day, dusk, or night from the `?wallpaper=` debug override or local time.
- The first style calculation reads the correct `html[data-time-theme]`; the main script then synchronizes body, Home, and the wallpaper stage, so non-day sessions no longer request a day asset first.
- Desktop window backdrops, dynamic wallpaper, and mobile wallpaper share the same early theme while the debug override remains available.
## Navigation and semantics
- The first Tab reveals a trilingual Skip to main content link that focuses the stable main landmark without changing the current route or address.
- Only the active route exposes one H1. Hidden routes stay outside the accessibility tree, while the Home composition and Neo-XP appearance remain unchanged.
- Card titles and safe Markdown headings now begin at H2, providing a stable hierarchy for later route-focus and semantic smoke tests.
## Unchanged boundaries
Public routes, accounts, Chat, article APIs, D1, and four-period visual assets are unchanged.
