[split-required] Split 58 monoliths across Python, Go, TypeScript (Phases 1-3)

Phase 1 — Python (klausur-service): 5 monoliths → 36 files
- dsfa_corpus_ingestion.py (1,828 LOC → 5 files)
- cv_ocr_engines.py (2,102 LOC → 7 files)
- cv_layout.py (3,653 LOC → 10 files)
- vocab_worksheet_api.py (2,783 LOC → 8 files)
- grid_build_core.py (1,958 LOC → 6 files)

Phase 2 — Go (edu-search-service, school-service): 8 monoliths → 19 files
- staff_crawler.go (1,402 → 4), policy/store.go (1,168 → 3)
- policy_handlers.go (700 → 2), repository.go (684 → 2)
- search.go (592 → 2), ai_extraction_handlers.go (554 → 2)
- seed_data.go (591 → 2), grade_service.go (646 → 2)

Phase 3 — TypeScript (admin-lehrer): 45 monoliths → 220+ files
- sdk/types.ts (2,108 → 16 domain files)
- ai/rag/page.tsx (2,686 → 14 files)
- 22 page.tsx files split into _components/ + _hooks/
- 11 component files split into sub-components
- 10 SDK data catalogs added to loc-exceptions
- Deleted dead backup index_original.ts (4,899 LOC)

All original public APIs preserved via re-export facades.
Zero new errors: Python imports verified, Go builds clean,
TypeScript tsc --noEmit shows only pre-existing errors.

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

admin-lehrer/components/ocr-pipeline/structure-detection-utils.ts

@@ -0,0 +1,106 @@
+/**
+ * Utility functions and constants for StepStructureDetection.
+ * Pure logic — no React, no 'use client' needed.
+ */
+
+export const KLAUSUR_API = '/klausur-api'
+
+export const COLOR_HEX: Record<string, string> = {
+  red: '#dc2626',
+  orange: '#ea580c',
+  yellow: '#ca8a04',
+  green: '#16a34a',
+  blue: '#2563eb',
+  purple: '#9333ea',
+}
+
+export type DetectionMethod = 'auto' | 'opencv' | 'ppdoclayout'
+
+/** Color map for PP-DocLayout region classes */
+export const DOCLAYOUT_CLASS_COLORS: Record<string, string> = {
+  table: '#2563eb',
+  figure: '#16a34a',
+  title: '#ea580c',
+  text: '#6b7280',
+  list: '#9333ea',
+  header: '#0ea5e9',
+  footer: '#64748b',
+  equation: '#dc2626',
+}
+
+const DOCLAYOUT_DEFAULT_COLOR = '#a3a3a3'
+
+export function getDocLayoutColor(className: string): string {
+  return DOCLAYOUT_CLASS_COLORS[className.toLowerCase()] || DOCLAYOUT_DEFAULT_COLOR
+}
+
+/**
+ * Convert a mouse event on the image container to image-pixel coordinates.
+ * The image uses object-contain inside an A4-ratio container, so we need
+ * to account for letterboxing.
+ */
+export function mouseToImageCoords(
+  e: React.MouseEvent,
+  containerEl: HTMLElement,
+  imgWidth: number,
+  imgHeight: number,
+): { x: number; y: number } | null {
+  const rect = containerEl.getBoundingClientRect()
+  const containerW = rect.width
+  const containerH = rect.height
+
+  // object-contain: image is scaled to fit, centered
+  const scaleX = containerW / imgWidth
+  const scaleY = containerH / imgHeight
+  const scale = Math.min(scaleX, scaleY)
+
+  const renderedW = imgWidth * scale
+  const renderedH = imgHeight * scale
+  const offsetX = (containerW - renderedW) / 2
+  const offsetY = (containerH - renderedH) / 2
+
+  const relX = e.clientX - rect.left - offsetX
+  const relY = e.clientY - rect.top - offsetY
+
+  if (relX < 0 || relY < 0 || relX > renderedW || relY > renderedH) {
+    return null
+  }
+
+  return {
+    x: Math.round(relX / scale),
+    y: Math.round(relY / scale),
+  }
+}
+
+/**
+ * Convert image-pixel coordinates to container-relative percentages
+ * for overlay positioning.
+ */
+export function imageToOverlayPct(
+  region: { x: number; y: number; w: number; h: number },
+  containerW: number,
+  containerH: number,
+  imgWidth: number,
+  imgHeight: number,
+): { left: string; top: string; width: string; height: string } {
+  const scaleX = containerW / imgWidth
+  const scaleY = containerH / imgHeight
+  const scale = Math.min(scaleX, scaleY)
+
+  const renderedW = imgWidth * scale
+  const renderedH = imgHeight * scale
+  const offsetX = (containerW - renderedW) / 2
+  const offsetY = (containerH - renderedH) / 2
+
+  const left = offsetX + region.x * scale
+  const top = offsetY + region.y * scale
+  const width = region.w * scale
+  const height = region.h * scale
+
+  return {
+    left: `${(left / containerW) * 100}%`,
+    top: `${(top / containerH) * 100}%`,
+    width: `${(width / containerW) * 100}%`,
+    height: `${(height / containerH) * 100}%`,
+  }
+}