build video support

Dockerfile

@@ -25,8 +25,8 @@ RUN npm run build
 FROM node:20-alpine AS runtime
 WORKDIR /app
 
-# Tesseract OCR — English language data only (add more langs as needed)
-RUN apk add --no-cache tesseract-ocr tesseract-ocr-data-eng
+# Tesseract OCR + ffmpeg (for video metadata via ffprobe)
+RUN apk add --no-cache tesseract-ocr tesseract-ocr-data-eng ffmpeg
 
 # Install production deps only
 COPY backend/package*.json ./