Replace CLI examples with multi-stage Dockerfile examples

- Web: Build app and serve with nginx
- Android: Extract APK from multi-stage build
- Linux: Build desktop app with minimal runtime
- Consolidated CI/CD section

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

README.md

@@ -32,34 +32,51 @@ Lightweight Flutter SDK images for CI/CD pipelines. Built on [Wolfi](https://wol
 - **Non-root** - Runs as unprivileged user (UID 65532)
 - **Supply chain security** - SBOM and SLSA provenance attestations included
 
-## Usage
+## Dockerfile Examples
 
-### Web
+### Web App
 
-```bash
-docker run --rm -v $(pwd):/app -w /app svrnty/flutter-sdk:web-latest \
-  flutter build web
+```dockerfile
+FROM svrnty/flutter-sdk:web-latest AS build
+COPY . /app
+WORKDIR /app
+RUN flutter pub get && flutter build web --release
+
+FROM nginx:alpine
+COPY --from=build /app/build/web /usr/share/nginx/html
+EXPOSE 80
 ```
 
-### Android
+### Android APK
 
-```bash
-docker run --rm -v $(pwd):/app -w /app svrnty/flutter-sdk:android-latest \
-  flutter build apk
+```dockerfile
+FROM svrnty/flutter-sdk:android-latest AS build
+COPY . /app
+WORKDIR /app
+RUN flutter pub get && flutter build apk --release
+
+FROM scratch
+COPY --from=build /app/build/app/outputs/flutter-apk/app-release.apk /
 ```
 
 ### Linux Desktop
 
-```bash
-docker run --rm -v $(pwd):/app -w /app svrnty/flutter-sdk:linux-latest \
-  flutter build linux
+```dockerfile
+FROM svrnty/flutter-sdk:linux-latest AS build
+COPY . /app
+WORKDIR /app
+RUN flutter pub get && flutter build linux --release
+
+FROM ubuntu:22.04
+RUN apt-get update && apt-get install -y libgtk-3-0 && rm -rf /var/lib/apt/lists/*
+COPY --from=build /app/build/linux/x64/release/bundle /app
+ENTRYPOINT ["/app/my_app"]
 ```
 
-## CI/CD Examples
-
-### GitHub Actions
+## CI/CD
 
 ```yaml
+# GitHub Actions / Gitea Actions
 jobs:
   build:
     runs-on: ubuntu-latest
@@ -67,31 +84,19 @@ jobs:
       image: svrnty/flutter-sdk:android-latest
     steps:
       - uses: actions/checkout@v4
+      - run: flutter pub get
       - run: flutter build apk --release
 ```
 
-### GitLab CI
-
 ```yaml
+# GitLab CI
 build:
   image: svrnty/flutter-sdk:android-latest
   script:
+    - flutter pub get
     - flutter build apk --release
 ```
 
-### Gitea Actions
-
-```yaml
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    container:
-      image: svrnty/flutter-sdk:android-latest
-    steps:
-      - uses: actions/checkout@v3
-      - run: flutter build apk --release
-```
-
 ## Tags
 
 - `<variant>-latest` - Latest stable Flutter release