fix: two-pass render - all countries as single white fill first

Canvas anti-aliasing creates semi-transparent edges between adjacent
polygons. Pass 1 draws ALL countries in one beginPath/fill call as
solid white - no seams possible. Pass 2 overdraws colored countries.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

layouts/shortcodes/world-map.html

@@ -110,11 +110,27 @@
 
     if (!geoData) return;
 
-    // Draw country fills (no separate land fill — gaps show ocean, not white)
+    // Pass 1: draw ALL countries as white in a single path (eliminates inter-polygon seams)
+    ctx.fillStyle = '#ffffff';
+    ctx.beginPath();
+    geoData.features.forEach(function(f) {
+      var geom = f.geometry;
+      if (geom.type === 'Polygon') {
+        geom.coordinates.forEach(function(ring) { traceRing(ctx, ring, sx, sy); });
+      } else if (geom.type === 'MultiPolygon') {
+        geom.coordinates.forEach(function(poly) {
+          poly.forEach(function(ring) { traceRing(ctx, ring, sx, sy); });
+        });
+      }
+    });
+    ctx.fill('evenodd');
+
+    // Pass 2: overdraw colored countries only
     geoData.features.forEach(function(f) {
       var id = String(f.id).padStart(3, '0');
       var c = byIsoNum[id];
-      ctx.fillStyle = c ? STATUS_COLORS[c.status] : '#ffffff';
+      if (!c) return; // skip no-data (already white)
+      ctx.fillStyle = STATUS_COLORS[c.status];
       drawGeometry(ctx, f.geometry, sx, sy, true);
     });