fix: add OCR image to CI/CD workflows (refs #64)

- Add OCR image build/push to staging workflow
- Add OCR service with image override to staging compose
- Add OCR service with image override to blue-green compose
- Add OCR image pull/deploy to production workflow
- Include mvp-ocr-staging in health checks

The OCR container is a shared service (like postgres/redis),
not part of blue-green deployment.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker-compose.staging.yml

@@ -55,6 +55,13 @@ services:
       - "traefik.http.routers.mvp-backend-health.priority=30"
       - "traefik.http.services.mvp-backend.loadbalancer.server.port=3001"
 
+  # ========================================
+  # OCR Service (Staging)
+  # ========================================
+  mvp-ocr:
+    image: ${OCR_IMAGE:-git.motovaultpro.com/egullickson/ocr:latest}
+    container_name: mvp-ocr-staging
+
   # ========================================
   # PostgreSQL (Staging - Separate Database)
   # ========================================