Add shelves page to game library; refresh bggpipe export

Port the export's physical shelf layout (.wall/.orow/.ocell) into the
scoped embed.css so /mygames/?g=shelves renders the wall in true
proportions, using the cream board color and accent-purple links for
legibility on the dark theme. Includes a fresh bggpipe re-export (new
Etherfields and Red Dragon Inn titles, updated art). embed.js/embed.css
are untouched by the export.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

static/games/britannia/index.html

@@ -22,7 +22,7 @@
 
 Britannia allows players to re-create this epic history, re-enacting important battles in some cases, altering the course of history in others. The game rules discourage players from making historically unrealistic moves, but also give players the freedom to alter Great Britain’s history in important ways, creating countless interesting “what if?” scenarios. What if Boudicca’s Revolt against the Romans had been more successful? What if the Romans and the Romano-British had repelled the Saxon invasions of the 5th and 6th centuries? What if William the Conqueror had died during the Norman invasion of 1066?
 
-In Britannia, the players will determine the destiny of a kingdom.</div>
+In Britannia, the players will determine the destiny of a kingdom.</div><div class="card"><div class="factrow"><b>where it lives</b> Library Kallax · D2</div></div>
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   <p>The Game Shelves · cataloged from shelf photos by