refactor: update findAppRoot function and adjust Dockerfile paths for consistency

app/Dockerfile

@@ -2,12 +2,12 @@ FROM node:24-trixie-slim AS build
 
 WORKDIR /app
 
-COPY app-new/backend/package*.json backend/
-COPY app-new/frontend/package*.json frontend/
+COPY backend/package*.json backend/
+COPY frontend/package*.json frontend/
 RUN cd backend && npm ci
 RUN cd frontend && npm ci
 
-COPY app-new .
+COPY . .
 
 RUN cd backend && npm run build
 RUN cd frontend && npm run build