Add Watchlists section — hub, 5 collection pages, build pipeline

- watchlists-hub.html: comic book panel grid, neon-teal/green/toucan palette,
  Rambla-only type hierarchy, CSS stagger entrance, wired to star map
- 5 collection pages built from *-watchlist.md sources via build.py:
  contentaddictionarchive, analogfrontier, culturaldecay,
  soundscapeanomalies, lastcinema
- build.py: parses MD files, generates self-contained HTML pages,
  updates hub subtitle with live counts
- index.html: Watchlists star node wired to Watchlists/watchlists-hub.html

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

index.html

@@ -694,7 +694,7 @@ body::after {
     { id: 'music',        label: 'Music',        sign: '♬',  x: 12, y: 44, href: '' },
     { id: 'images',       label: 'Images',       sign: '絵',  x: 55, y: 35, href: 'Images/images.html' },
     { id: 'playlists',    label: 'Playlists',    sign: '≡',  x: 78, y: 50, href: 'Playlists/playlists.html' },
-    { id: 'watchlists',   label: 'Watchlists',   sign: '視',  x: 22, y: 66, href: '' },
+    { id: 'watchlists',   label: 'Watchlists',   sign: '視',  x: 22, y: 66, href: 'Watchlists/watchlists-hub.html' },
     { id: 'toolsntoys',   label: 'ToolsnToys',   sign: '⚙',  x: 50, y: 72, href: '' },
     { id: 'creatorlists', label: 'Creatorlists', sign: '創',  x: 75, y: 70, href: '' }
   ];