fix: resolve chart visibility issues after CSV upload

- Add fixed width to sidebar (w-64) to prevent layout collapse
- Change chart container from flex-1 to w-full h-full for proper sizing
- Chart now properly displays after CSV upload

src/app/page.tsx

@@ -26,7 +26,7 @@ export default function Home() {
   return (
     <div className="flex h-screen">
       {/* Sidebar */}
-      <aside className="flex flex-col">
+      <aside className="w-64 flex-shrink-0 flex flex-col border-r border-border">
         <div className="p-4 border-b border-border">
           <h1 className="text-xl font-bold">Candle Annotator</h1>
         </div>

src/components/CandleChart.tsx

@@ -266,7 +266,7 @@ const CandleChart = forwardRef<CandleChartHandle, CandleChartProps>(
     }
 
     return (
-      <div className="flex-1 relative">
+      <div className="w-full h-full relative">
         <div ref={chartContainerRef} className="absolute inset-0" />
         <SvgOverlay
           chart={chartRef.current}