style(design): FINDING-004 — add tabular-nums to financial numbers

Add font-variant-numeric: tabular-nums to .metric-value and .stats-value
so financial figures align properly when values change.

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

src/assets/css/components/cards.css

@@ -88,6 +88,7 @@
   font-weight: var(--font-bold);
   color: var(--color-text);
   line-height: var(--leading-tight);
+  font-variant-numeric: tabular-nums;
   margin-bottom: var(--space-xs);
 }
 
@@ -404,6 +405,7 @@
   font-weight: var(--font-bold);
   line-height: var(--leading-tight);
   font-family: var(--font-mono, monospace);
+  font-variant-numeric: tabular-nums;
   color: var(--color-text);
 }