feat: color bar respects edits + column pattern auto-correction

- Color bar (red/colored indicator) now only shows when word_boxes
  text still matches the cell text — editing the cell hides stale colors
- New "Auto-Korrektur" button: detects dominant prefix+number patterns
  per column (e.g. p.70, p.71) and completes partial entries (.65 → p.65)
  — requires 3+ matching entries before correcting

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

admin-lehrer/components/grid-editor/GridTable.tsx

@@ -443,7 +443,6 @@ export function GridTable({
                   const isBold = col.bold || cell?.is_bold
                   const isLowConf = cell && cell.confidence > 0 && cell.confidence < 60
                   const isMultiSelected = selectedCells?.has(cellId)
-                  const cellColor = getCellColor(cell)
                   // Show per-word colored display only when word_boxes
                   // match the cell text.  Post-processing steps (e.g. 5h
                   // slash-IPA → bracket conversion) modify cell.text but
@@ -451,6 +450,8 @@ export function GridTable({
                   // plain input when they diverge.
                   const wbText = cell?.word_boxes?.map((wb) => wb.text).join(' ') ?? ''
                   const textMatches = !cell?.text || wbText === cell.text
+                  // Color bar only when word_boxes still match edited text
+                  const cellColor = textMatches ? getCellColor(cell) : null
                   const hasColoredWords =
                     textMatches &&
                     (cell?.word_boxes?.some(