docs: add README.md in pkg/harvester (#661)

Signed-off-by: Andy Lee <andy.lee@suse.com>

pkg/harvester/README.md

@@ -0,0 +1,178 @@
+# harvester-ui-extension
+
+The Harvester UI Extension is a Rancher extension that provides the user interface for [Harvester](https://harvesterhci.io) within the [Rancher Dashboard](https://github.com/rancher/dashboard).
+
+> **Note:**
+> This extension is available starting from **Rancher 2.10.0**. Ensure your Rancher version is **2.10.0 or later** to access Harvester integration.
+
+## Installation
+
+For detailed installation instructions, please refer to the [official Harvester documentation](https://docs.harvesterhci.io/v1.5/rancher/harvester-ui-extension#installation-on-rancher-210).
+
+
+## Development Setup
+
+Ensure **Node.js v20 or later** is installed for development and debugging.
+
+### Standalone Mode
+
+Run the extension standalone with hot reload at `https://localhost:8005`.
+
+```bash
+# Install dependencies
+yarn install
+
+# Start the development server
+RANCHER_ENV=harvester API=https://your-harvester-ip yarn dev
+
+# Example with specific server version
+RANCHER_ENV=harvester VUE_APP_SERVER_VERSION=v1.5.0 API=https://192.168.1.123 yarn dev
+```
+
+You may also define environment variables in a `.env` file:
+
+```env
+RANCHER_ENV=harvester
+VUE_APP_SERVER_VERSION=v1.5.0
+API=https://192.168.1.123
+```
+
+### Rancher Integration Mode
+
+To run as a Rancher extension, follow the [Rancher UI Extension Guide](https://extensions.rancher.io/extensions/next/extensions-getting-started#running-the-app).
+
+```bash
+API=https://your-rancher-ip yarn dev
+```
+
+## Commit Message Guidelines
+
+This project uses [commit-lint](https://commitlint.js.org/) with [Conventional Commits](https://www.conventionalcommits.org/) to ensure consistent and meaningful commit messages.
+
+### Commit Message Format
+
+All commit messages must follow the conventional commit format:
+
+```
+<type>[optional scope]: <description>
+
+[optional body]
+
+[optional footer(s)]
+```
+
+### Supported Types
+
+- **feat**: New features
+- **fix**: Bug fixes
+- **docs**: Documentation changes
+- **style**: Code style changes (formatting, missing semicolons, etc.)
+- **refactor**: Code refactoring
+- **perf**: Performance improvements
+- **test**: Adding or updating tests
+- **build**: Build system or external dependencies
+- **ci**: CI/CD changes
+- **chore**: Other changes that don't modify src or test files
+- **revert**: Reverts a previous commit
+- **wip**: Work in progress
+- **deps**: Dependency updates
+- **security**: Security fixes
+
+### Examples
+
+```bash
+# Feature
+git commit -m "feat: add new virtual machine creation wizard"
+
+# Bug fix
+git commit -m "fix: resolve memory leak in VM console"
+
+# Documentation
+git commit -m "docs: update installation instructions"
+
+# Breaking change
+git commit -m "feat!: change API endpoint structure
+
+BREAKING CHANGE: The /api/v1/vms endpoint has been replaced with /api/v2/vms"
+```
+
+### Git Hooks
+
+The project uses [Husky](https://typicode.github.io/husky/) to automatically validate commit messages and run linting before commits:
+
+- **pre-commit**: Runs ESLint to ensure code quality
+- **commit-msg**: Validates commit message format using commit-lint
+
+These hooks are automatically installed when you run `yarn install`.
+
+### Manual Validation
+
+You can manually validate commit messages:
+
+```bash
+# Validate the last commit
+yarn commitlint
+
+# Validate a specific commit
+npx commitlint --from <commit-hash>
+
+# Validate a range of commits
+npx commitlint --from <start-hash> --to <end-hash>
+```
+
+## Branch Structure
+
+- **`main`** – Main development branch
+- **`release-harvester-vX.Y`** – Stable release branches per version series
+- **`vX.Y-head`** – Testing branches for ongoing changes to extension builds in each release series
+
+> **Note:**
+> The `vX.Y-head` branches are auto-generated and kept in sync with release branches. Use these for testing the latest changes in each version series.
+
+## Testing Guidelines
+
+### UI Extension Testing
+
+To validate changes in a release series, switch to the appropriate `vX.Y-head` branch. For main branch testing, use `main-head`.
+
+- Examples:
+  - Test `1.0.x` series → `v1.0-head`
+  - Test `1.5.x` series → `v1.5-head`
+
+**Steps:**
+1. Navigate to **Rancher UI** → **Local** → **App** → **Repositories**
+2. Refresh the Harvester repository using the target `vX.Y-head` branch
+3. Go to the **Extensions** page and install the desired version
+
+### Standalone Mode Testing
+
+To test the standalone UI, configure Harvester to load the UI from an external source.
+
+- Examples of `ui-index`:
+  - Main branch → `https://releases.rancher.com/harvester-ui/dashboard/latest/index.html`
+  - Release series `1.5.x` → `https://releases.rancher.com/harvester-ui/dashboard/release-harvester-v1.5/index.html`
+
+**Steps:**
+1. Go to **Harvester UI** → **Advanced** → **Settings** → **UI**
+2. Set **ui-source** to `External`
+3. Set **ui-index** to the desired URL
+
+## Contributing
+
+If you want to contribute, start by reading this document, then visit our [Getting Started guide](https://extensions.rancher.io/extensions/next/extensions-getting-started) to learn how to develop and submit changes.
+
+## License
+
+Copyright (c) 2014-2025 [SUSE, LLC.](https://www.suse.com/)
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+[http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0)
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.