docs(nvm): Document nvm usage in Dockerfiles and CI/CD workflows

- Add comprehensive NVM usage section to README
- Document Dockerfile RUN command usage
- Document CI/CD workflow integration
- Explain nvm vs npmci comparison
- Add technical implementation notes to readme.hints.md
- Update changelog with v5.0.147 feature details

Includes:
- Direct nvm usage examples for Dockerfiles
- CI/CD workflow YAML examples
- Version persistence behavior documentation
- Multi-version testing examples
- Technical architecture details
- Maintenance guidelines

readme.md

@@ -41,6 +41,65 @@ RUN npmci install 14.17.0
 
 In this example, `npmci` installs Node.js version `14.17.0` and sets it as the default.
 
+### Using NVM in Dockerfiles
+
+The base image includes **nvm (Node Version Manager)** for flexible Node.js version management. Use nvm commands directly in Dockerfile RUN statements without any sourcing required:
+
+```dockerfile
+FROM registry.gitlab.com/hosttoday/ht-docker-node:latest
+
+# Use nvm directly - no sourcing needed
+RUN nvm install 18.20.0
+RUN nvm use 18 && npm install
+
+# Or chain commands
+RUN nvm install 19.0.0 && nvm use 19 && npm ci
+```
+
+**Important**: Each RUN command is a separate shell. To persist version changes across RUN commands, set a new default:
+
+```dockerfile
+RUN nvm install 18.20.0 && nvm alias default 18
+# Subsequent RUN commands will use v18 by default
+```
+
+### Using NVM in CI/CD Workflows
+
+NVM is automatically available in CI/CD workflow scripts when using `bash -c`:
+
+```yaml
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    container:
+      image: registry.gitlab.com/hosttoday/ht-docker-node:latest
+
+    steps:
+      - name: Use specific Node version
+        run: |
+          nvm install 18.20.0
+          nvm use 18
+          npm install
+          npm test
+
+      - name: Test multiple versions
+        run: |
+          for version in 16 18 20; do
+            nvm install $version
+            nvm use $version
+            npm test
+          done
+```
+
+### NVM vs npmci
+
+Both tools are available in the image:
+
+- **nvm**: Standard Node version manager, works in Dockerfiles and CI/CD workflows
+- **npmci**: CI-focused wrapper with additional shipzone.io features
+
+Choose based on your preference - they work together seamlessly.
+
 ### Custom Dockerfile with `npmci` and your Node.js App
 
 You can create a custom Dockerfile for your Node.js application using the `:npmci` flavour: