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/useGridEditor.ts

@@ -655,6 +655,81 @@ export function useGridEditor(sessionId: string | null) {
     [grid, pushUndo],
   )
 
+  // ------------------------------------------------------------------
+  // Column pattern auto-correction
+  // ------------------------------------------------------------------
+
+  /**
+   * Detect dominant prefix+number patterns per column and complete
+   * partial matches.  E.g. if 3+ cells read "p.70", "p.71", etc.,
+   * a cell reading ".65" is corrected to "p.65".
+   * Returns the number of corrections made.
+   */
+  const autoCorrectColumnPatterns = useCallback(() => {
+    if (!grid) return 0
+    pushUndo(grid.zones)
+
+    let totalFixed = 0
+    const numberPattern = /^(.+?)(\d+)\s*$/
+
+    setGrid((prev) => {
+      if (!prev) return prev
+      return {
+        ...prev,
+        zones: prev.zones.map((zone) => {
+          // Group cells by column
+          const cellsByCol = new Map<number, { cell: (typeof zone.cells)[0]; idx: number }[]>()
+          zone.cells.forEach((cell, idx) => {
+            const arr = cellsByCol.get(cell.col_index) || []
+            arr.push({ cell, idx })
+            cellsByCol.set(cell.col_index, arr)
+          })
+
+          const newCells = [...zone.cells]
+
+          for (const [, colEntries] of cellsByCol) {
+            // Count prefix occurrences
+            const prefixCounts = new Map<string, number>()
+            for (const { cell } of colEntries) {
+              const m = cell.text.trim().match(numberPattern)
+              if (m) {
+                prefixCounts.set(m[1], (prefixCounts.get(m[1]) || 0) + 1)
+              }
+            }
+
+            // Find dominant prefix (>= 3 occurrences)
+            let dominantPrefix = ''
+            let maxCount = 0
+            for (const [prefix, count] of prefixCounts) {
+              if (count >= 3 && count > maxCount) {
+                dominantPrefix = prefix
+                maxCount = count
+              }
+            }
+            if (!dominantPrefix) continue
+
+            // Fix partial matches — entries that are just [.?\s*]NUMBER
+            for (const { cell, idx } of colEntries) {
+              const text = cell.text.trim()
+              if (!text || text.startsWith(dominantPrefix)) continue
+
+              const numMatch = text.match(/^[.\s]*(\d+)\s*$/)
+              if (numMatch) {
+                newCells[idx] = { ...newCells[idx], text: `${dominantPrefix}${numMatch[1]}` }
+                totalFixed++
+              }
+            }
+          }
+
+          return { ...zone, cells: newCells }
+        }),
+      }
+    })
+
+    if (totalFixed > 0) setDirty(true)
+    return totalFixed
+  }, [grid, pushUndo])
+
   // ------------------------------------------------------------------
   // Multi-select & bulk formatting
   // ------------------------------------------------------------------
@@ -805,5 +880,6 @@ export function useGridEditor(sessionId: string | null) {
     toggleCellSelection,
     clearCellSelection,
     toggleSelectedBold,
+    autoCorrectColumnPatterns,
   }
 }