feat: Sprint 2 — TrOCR ONNX, PP-DocLayout, Model Management

D2: TrOCR ONNX export script (printed + handwritten, int8 quantization)
D3: PP-DocLayout ONNX export script (download or Docker-based conversion)
B3: Model Management admin page (PyTorch vs ONNX status, benchmarks, config)
A4: TrOCR ONNX service with runtime routing (auto/pytorch/onnx via TROCR_BACKEND)
A5: PP-DocLayout ONNX detection with OpenCV fallback (via GRAPHIC_DETECT_BACKEND)
B4: Structure Detection UI toggle (OpenCV vs PP-DocLayout) with class color coding
C3: TrOCR-ONNX.md documentation
C4: OCR-Pipeline.md ONNX section added
C5: mkdocs.yml nav updated, optimum added to requirements.txt

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

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

@@ -233,6 +233,15 @@ export interface ExcludeRegion {
   label?: string
 }
 
+export interface DocLayoutRegion {
+  x: number
+  y: number
+  w: number
+  h: number
+  class_name: string
+  confidence: number
+}
+
 export interface StructureResult {
   image_width: number
   image_height: number
@@ -246,6 +255,9 @@ export interface StructureResult {
   word_count: number
   border_ghosts_removed?: number
   duration_seconds: number
+  /** PP-DocLayout regions (only present when method=ppdoclayout) */
+  layout_regions?: DocLayoutRegion[]
+  detection_method?: 'opencv' | 'ppdoclayout'
 }
 
 export interface StructureBox {