fix: correct backend path in Dockerfile for HF deployment

Dockerfile

@@ -30,8 +30,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY backend/requirements.txt ./
 RUN pip install --no-cache-dir -r requirements.txt
 
-# Copy backend code
-COPY backend/ ./backend/
+# Copy backend code to /app (NOT /app/backend)
+COPY backend/ ./
 
 # Copy built frontend from builder stage
 COPY --from=frontend-builder /app/frontend/dist ./frontend/dist
@@ -44,4 +44,4 @@ ENV PORT=7860
 EXPOSE 7860
 
 # Start FastAPI (serves API + frontend static files)
-CMD ["uvicorn", "backend.main:app", "--host", "0.0.0.0", "--port", "7860"]
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "7860"]