Refine Results section: brain cutout, colorbar, labels, and Korean UX copy

- Canvas-based white background removal for brain surface images
- Custom colorbar with 활성 차이 label and scale values
- Korean-friendly titles and legends for non-expert readability
- Spacing and layout adjustments across all Results sub-cards
- Minor fixes in DataUpload, ModelSelection, TaskSelection sections

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: bohee-connectome

src/sections/DataUploadSection.tsx

@@ -65,7 +65,7 @@ export default function DataUploadSection({ modality, onModalityChange }: Props)
           <h2 className="text-4xl md:text-5xl font-bold text-text-primary mb-4">
             Data Upload
           </h2>
-          <p className="text-text-secondary text-lg mb-12 max-w-2xl">
+          <p className="text-text-secondary text-lg mb-12 max-w-3xl">
             Upload subject brain data. The system automatically identifies the data modality
             based on file extension.
           </p>

src/sections/ModelSelectionSection.tsx

@@ -73,7 +73,7 @@ export default function ModelSelectionSection({ selectedModel }: Props) {
           <h2 className="text-4xl md:text-5xl font-bold text-text-primary mb-4">
             Foundation Model Selection
           </h2>
-          <p className="text-text-secondary text-lg mb-4 max-w-2xl">
+          <p className="text-text-secondary text-lg mb-4 max-w-3xl">
             The appropriate model is automatically selected based on the detected data modality.
           </p>