Add a filled-outline house icon to the icon set

"house" is a closed house shape with the door cut out, next to the
existing line-drawn "home". Written through scripts/build-icons.mjs
into the Twig template and the validator allowlist.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

templates/blocks/icon.html.twig

@@ -68,6 +68,7 @@
     heart: 'M12 20s-7.5-4.6-7.5-10A4.3 4.3 0 0 1 12 7.4 4.3 4.3 0 0 1 19.5 10c0 5.4-7.5 10-7.5 10Z',
     star: 'm12 3 2.7 5.9 6.3.7-4.7 4.3 1.3 6.1L12 17l-5.6 3 1.3-6.1L3 9.6l6.3-.7Z',
     home: 'm3 11.5 9-7.5 9 7.5M5.5 10v10h13V10M10 20v-6.5h4V20',
+    house: 'M4 10.5 12 4l8 6.5V19a1 1 0 0 1-1 1h-4.5v-5.5h-5V20H5a1 1 0 0 1-1-1Z',
     building: 'M5 21V4h10v17m0-12h4v12M3 21h18M8.5 7.5h3m-3 3.5h3m-3 3.5h3',
     wrench: 'M14.5 3.5a5 5 0 0 0-4.6 6.9L3.5 16.8a1.9 1.9 0 0 0 2.7 2.7l6.4-6.4a5 5 0 0 0 6.9-4.6l-3 3-3-1-1-3Z',
     hammer: 'M14 8.5 4.5 18a1.5 1.5 0 0 0 2.1 2.1L16 10.5M11 6l3-3 3.5 1L21 7.5 18.5 10l-2-2-2.5 2.5Z',