update Dockerfile

Dockerfile

@@ -31,6 +31,8 @@ RUN pip install --no-cache-dir -r requirements-docker.txt \
     --extra-index-url https://download.pytorch.org/whl/cpu
 
 # ---- Copy application code ----
+# Cache-bust: forces COPY and all downstream layers to rebuild
+ARG DETECTIFAI_BUILD_TS=0
 # Core application files
 COPY app.py config.py main_pipeline.py database_video_service.py \
      object_detection.py behavior_analysis_integrator.py \