feat: display detected text colors in grid editor UI

- Add color/color_name/recovered fields to OcrWordBox type
- GridTable: show colored text + left-edge color indicator strip
- GridEditor: show color stats and recovered count in summary bar

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

admin-lehrer/app/(admin)/ai/ocr-pipeline/types.ts

@@ -227,6 +227,9 @@ export interface OcrWordBox {
   width: number   // px
   height: number  // px
   conf: number
+  color?: string       // hex color of detected text, e.g. '#dc2626'
+  color_name?: string  // 'black' | 'red' | 'blue' | 'green' | 'orange' | 'purple' | 'yellow'
+  recovered?: boolean  // true if this word was recovered via color detection
 }
 
 export interface GridCell {