feat(site): phase 17 - per-game module pages, /runicnpc/, and checkTerms over the built site

PLAN.md §16 phase 17, built on the org lead's answers of 2026-10-22,
recorded as D75-D79 (count of record 79).

- D75: core marketing pages describe what a game module adds in core's
  words. "Game intelligence" became "What a game module adds"; each
  game's own list moved to src/data/games/ and renders only on the new
  /modules/uo/ and /modules/rust/. /modules/ is a card per game.
- The page-side capability check is per game (assertGameCoverage), the
  item phase 13 moved here.
- D76: the homepage keeps its game screenshot, labelled. screens.mjs
  entries may carry `game` (D67); Screenshot.astro and the app grid
  print the game's name and mark the figure data-game.
- D77: /app/ describes the Rust screens (released the same day).
- D78: /runicnpc/, the standalone page, is in the header and footer;
  the narrow header was re-measured so five links keep two rows.
- D79: checkTerms.mjs --built reads every built page's visible text
  after the build; game routes and data-game elements allow their
  game's words. Proven against ten plants. Still the twelfth check.
- Re-read fixes: /architecture/'s "two machines is also the maximum",
  Discord "guild" on /integrations/, and collection.mjs against what
  Steam sign-in and the Rust module keep (PLAY_DATA_SAFETY.md
  regenerated; the Play answers are unchanged).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

src/components/Header.astro

@@ -28,6 +28,8 @@ const brand = renderBrand(Astro);
 const links = [
   { href: '/features/', label: 'Features' },
   { href: '/docs/', label: 'Docs' },
+  // D78 (phase 17): the standalone RunicNPC page, for a Rust server owner who runs no site.
+  { href: '/runicnpc/', label: 'RunicNPC' },
   { href: '/app/', label: 'App' },
   { href: '/community/', label: 'Community' },
 ];