fix: make SparkLine SVG responsive with viewBox

SVG was using fixed width/height attributes causing clipping in
smaller containers. Now uses viewBox for coordinate system and
w-full h-full classes to fill container properly.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/lib/components/common/SparkLine.svelte

@@ -43,7 +43,7 @@
 	});
 </script>
 
-<svg {width} {height} class="overflow-visible">
+<svg viewBox="0 0 {width} {height}" class="w-full h-full overflow-visible" preserveAspectRatio="none">
 	<defs>
 		<linearGradient id="sparkGradient-{color}" x1="0%" y1="0%" x2="0%" y2="100%">
 			<stop offset="0%" style="stop-color:{color};stop-opacity:0.3" />