feat: Agregar soporte OCR con Tesseract para PDFs escaneados

- Integrar Tesseract OCR para leer PDFs escaneados automáticamente
- Detectar automáticamente si el PDF tiene texto o requiere OCR
- Agregar servicio ocr_service.py con funciones de OCR
- Actualizar Dockerfile con tesseract-ocr, tesseract-ocr-spa y poppler-utils
- Agregar variables de configuración OCR (OCR_ENABLED, OCR_LANGUAGE, OCR_DPI, OCR_TIMEOUT)
- Crear endpoint de debug para ver texto extraído (/api/v1/debug/extract-text)
- Agregar scripts de instalación y prueba (install_ocr.ps1, test_ocr.py, debug_pdf.ps1)
- Documentación completa (OCR_SETUP.md, DOCKER_OCR.md, COMO_PROBAR.md)
- Actualizar docker-compose.yml con variables de entorno OCR
- Modificar pdf_text.py para usar OCR cuando sea necesario
- Actualizar requirements.txt con pytesseract, Pillow, pdf2image

app/api/v1/debug.py

@@ -0,0 +1,87 @@
+"""Debug endpoint to see extracted text from PDF."""
+from fastapi import APIRouter, Depends, HTTPException, UploadFile, File, status
+from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
+import logging
+
+from app.core.config import get_settings
+from app.core.security import decode_access_token
+from app.services.pdf_text import extract_text_from_pdf, PDFExtractionError
+
+logger = logging.getLogger(__name__)
+router = APIRouter(prefix="/v1/debug", tags=["Debug"])
+security = HTTPBearer()
+settings = get_settings()
+
+
+def get_current_user(credentials: HTTPAuthorizationCredentials = Depends(security)) -> str:
+    """Validate JWT token."""
+    payload = decode_access_token(credentials.credentials)
+    return payload.get("sub")
+
+
+@router.post("/extract-text")
+async def debug_extract_text(
+    file: UploadFile = File(...),
+    current_user: str = Depends(get_current_user)
+):
+    """
+    Debug endpoint to see raw extracted text from PDF.
+    Shows exactly what text was extracted and which method was used.
+    """
+    # Validate file type
+    if file.content_type != "application/pdf":
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=f"Invalid file type: {file.content_type}. Only PDF files are allowed."
+        )
+    
+    # Read file
+    pdf_bytes = await file.read()
+    
+    # Validate size
+    file_size_mb = len(pdf_bytes) / (1024 * 1024)
+    if file_size_mb > settings.max_file_mb:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=f"File size ({file_size_mb:.2f} MB) exceeds maximum allowed size of {settings.max_file_mb} MB"
+        )
+    
+    # Extract text
+    try:
+        text, page_count, extraction_method = extract_text_from_pdf(
+            pdf_bytes,
+            enable_ocr=settings.ocr_enabled,
+            ocr_lang=settings.ocr_language
+        )
+        
+        # Get first and last 500 characters
+        text_preview_start = text[:500] if len(text) > 500 else text
+        text_preview_end = text[-500:] if len(text) > 500 else ""
+        
+        return {
+            "status": "success",
+            "extraction_info": {
+                "method": extraction_method,
+                "pages": page_count,
+                "total_characters": len(text),
+                "total_words": len(text.split()),
+                "total_lines": len(text.split('\n'))
+            },
+            "text_preview": {
+                "first_500_chars": text_preview_start,
+                "last_500_chars": text_preview_end if text_preview_end else None
+            },
+            "full_text": text,  # Complete extracted text
+            "ocr_settings": {
+                "ocr_enabled": settings.ocr_enabled,
+                "ocr_language": settings.ocr_language,
+                "ocr_dpi": settings.ocr_dpi
+            }
+        }
+        
+    except PDFExtractionError as e:
+        logger.error(f"Extraction failed: {str(e)}")
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"Failed to extract text from PDF: {str(e)}"
+        )