SpreadsheetView: formatting improvements for Excel-like display

Height: sheet height auto-calculated from row count (26px/row + toolbar),
no more cutoff at 21 rows. Row count set to exact (no padding).

Box borders: thick colored outside border + thin inner grid lines.
Content zone: light gray grid lines on all cells.

Headers: bold (bl=1) for is_header rows. Larger font detected via
word_box height comparison (>1.3x median → fs=12 + bold).

Box cells: light tinted background from box_bg_hex.
Header cells in boxes: slightly stronger tint.

Multi-line cells: text wrap enabled (tb='2'), \n preserved.
Bullet points (•) and indentation preserved in cell text.

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

admin-lehrer/components/ocr-kombi/StepAnsicht.tsx

@@ -100,9 +100,9 @@ export function StepAnsicht({ sessionId, onNext }: StepAnsichtProps) {
           )}
         </div>
 
-        {/* RIGHT: Fortune Sheet */}
+        {/* RIGHT: Fortune Sheet — height adapts to content */}
         <div className="flex-1 border border-gray-300 dark:border-gray-600 rounded-lg overflow-hidden bg-white dark:bg-gray-900">
-          <SpreadsheetView gridData={gridData} height={Math.max(650, leftHeight - 10)} />
+          <SpreadsheetView gridData={gridData} height={Math.max(700, leftHeight)} />
         </div>
       </div>
     </div>