update mih ui with stable flutter and optimised docker file caching

mih_ui/Dockerfile

@@ -3,17 +3,19 @@ FROM debian:latest AS build-env
 
 # Install necessary dependencies for Flutter 
 RUN apt-get update && apt-get install -y \
-    curl git wget unzip libglu1-mesa fonts-droid-fallback python3 \
-    && rm -rf /var/lib/apt/lists/*
+	curl git wget unzip libglu1-mesa fonts-droid-fallback python3 \
+	&& rm -rf /var/lib/apt/lists/*
 
 # Clone Flutter SDK 
-RUN git clone -b flutter-3.32-candidate.0 https://github.com/flutter/flutter.git /usr/local/flutter
+RUN git clone -b stable https://github.com/flutter/flutter.git /usr/local/flutter
 ENV PATH="/usr/local/flutter/bin:/usr/local/flutter/bin/cache/dart-sdk/bin:${PATH}"
 
 # Build the Flutter web app 
+RUN flutter config --enable-web && flutter precache --web
 WORKDIR /app
+COPY pubspec.yaml pubspec.lock ./
+RUN flutter pub get
 COPY . .
-RUN flutter config --enable-web
 RUN flutter build web --release -t ./lib/main_prod.dart
 
 # --- STAGE 2: The Final Production Image ---
@@ -24,13 +26,13 @@ COPY --from=build-env /app/build/web /usr/share/nginx/html
 
 # Create the Nginx config inside the Dockerfile to handle SPA routing 
 RUN echo 'server { \
-    listen 83; \
-    location / { \
-    root /usr/share/nginx/html; \
-    index index.html; \
-    try_files $uri $uri/ /index.html; \
-    } \
-    }' > /etc/nginx/conf.d/default.conf
+	listen 83; \
+	location / { \
+	root /usr/share/nginx/html; \
+	index index.html; \
+	try_files $uri $uri/ /index.html; \
+	} \
+	}' > /etc/nginx/conf.d/default.conf
 
 EXPOSE 83
-CMD ["nginx", "-g", "daemon off;"]
+CMD ["nginx", "-g", "daemon off;"]