docs: redesign site with deep-space terminal branding

[hahwul]

Full redesign of the documentation + landing site around the rocket logo and urx's real monochrome/terminal identity, replacing the generic blue + Inter theme.

Highlights

• New landing (dedicated sidebar-free template): animated rocket hero with ignition thrust + starfield, authentic terminal demo (real urx output), 7-provider grid, feature bento with visual variation, and a Collect → Filter → Validate → Output pipeline mapped to real flags.
• Palette: deep-space void / paper with a single ignition-orange accent (#ff5b29); code blocks stay dark in both themes (embedded-terminal look).
• Type: Space Grotesk (display), Inter (body), JetBrains Mono (mono/terminal).
• Theming: light/dark toggle with a no-flash inline script + localStorage; respects prefers-color-scheme.
• Motion: scroll-reveal via IntersectionObserver (no scroll listeners), rocket float/thrust, hover states, all gated behind prefers-reduced-motion.
• Docs shell: refined nav + sidebar (shared partials _docsnav.html / _sidebar.html), terminal-style code blocks, restyled tables/callouts, space-themed 404.
• AGENTS.md updated for the new template/style architecture.

Verification

• hwaro build clean (14 pages).
• Reviewed light, dark, and mobile via headless Chrome.
• Zero em/en dashes in shipped content; single accent color; theme-consistent sections.