📝 Add README with Flutter workflow details (#2)

Author: IamPekka058

.github/workflows/test-build-release.yml .github/workflows/workflow-build.yml.github/workflows/test-build-release.yml renamed to .github/workflows/workflow-build.yml

@@ -1,3 +1,132 @@
-# flutter-workflow
+# Flutter Workflow
 
-TODO: README
+[![Release](https://img.shields.io/github/v/release/RubberDuckCrew/flutter-workflow?style=flat-square&color=blue)](https://github.com/RubberDuckCrew/flutter-workflow/releases)
+[![Build Status](https://img.shields.io/github/actions/workflow/status/RubberDuckCrew/flutter-workflow/check-release.yml?style=flat-square&label=Check%20and%20Release&color=lime)](https://github.com/RubberDuckCrew/flutter-workflow/actions/workflows/check-release.yml)
+[![Last Commit](https://img.shields.io/github/last-commit/RubberDuckCrew/flutter-workflow?style=flat-square&color=orange)](https://github.com/RubberDuckCrew/flutter-workflow/commits/main)
+[![License: MIT](https://img.shields.io/github/license/RubberDuckCrew/flutter-workflow?style=flat-square&color=yellow)](LICENSE)
+
+A reusable GitHub Actions workflow to **test, build, analyze, and release Flutter applications** with minimal setup.
+
+## Features
+
+- Runs **formatting, analysis, and tests** automatically.
+- Builds **APK and App Bundle (AAB)** artifacts.
+- Supports **size analysis builds**.
+- Automatically **signs builds** when keystore secrets are provided.
+- Uploads build artifacts (APK, AAB, symbols).
+- Can **comment artifact links on pull requests** (via artifact2pr).
+- Supports **on-demand builds via PR label** (`⚗️ Request Build`).
+- Creates **draft GitHub releases** with attached artifacts.
+
+## Inputs
+
+| Name                | Description                                                    | Required | Default |
+| ------------------- | -------------------------------------------------------------- | -------- | ------- |
+| `release-version`   | Version to release (e.g., `1.2.3`, `v` is added automatically) | No       | —       |
+| `app-name`          | Name of the app (used for artifact naming)                     | No       | —       |
+| `build-type`        | Type of build (`test`, `build`, `size-analysis`, `release`)    | No       | `test`  |
+| `java-version`      | Java version used for Android build                            | No       | `21`    |
+| `working-directory` | Directory of the Flutter project                               | No       | `.`     |
+| `bot-app-id`        | GitHub App ID used for release creation                        | No       | —       |
+
+## Secrets
+
+| Name                  | Description             | Required |
+| --------------------- | ----------------------- | -------- |
+| `KEY_PASSWORD`        | Keystore key password   | No       |
+| `KEYSTORE_PASSWORD`   | Keystore password       | No       |
+| `KEY_ALIAS`           | Keystore alias          | No       |
+| `KEYSTORE_BASE64`     | Base64 encoded keystore | No       |
+| `BOT_APP_PRIVATE_KEY` | GitHub App private key  | No       |
+
+## Usage
+
+Call this workflow from another repository:
+
+```yaml
+name: Use Flutter Workflow
+
+on:
+  pull_request:
+  push:
+    tags:
+      - "*"
+
+jobs:
+  flutter:
+    uses: RubberDuckCrew/flutter-workflow/.github/workflows/workflow-build.yml@v1
+    with:
+      app-name: my-app
+      build-type: build
+```
+
+### Release Example
+
+```yaml
+jobs:
+  release:
+    uses: RubberDuckCrew/flutter-workflow/.github/workflows/workflow-build.yml@v1
+    with:
+      app-name: my-app
+      build-type: release
+      release-version: 1.2.3
+    secrets:
+      KEY_PASSWORD: ${{ secrets.KEY_PASSWORD }}
+      KEYSTORE_PASSWORD: ${{ secrets.KEYSTORE_PASSWORD }}
+      KEY_ALIAS: ${{ secrets.KEY_ALIAS }}
+      KEYSTORE_BASE64: ${{ secrets.KEYSTORE_BASE64 }}
+      BOT_APP_PRIVATE_KEY: ${{ secrets.BOT_APP_PRIVATE_KEY }}
+```
+
+## Build Triggers
+
+The build job runs when:
+
+- A **tag is pushed**
+- The PR has the label **`⚗️ Request Build`**
+- `build-type` is set to `build`, `size-analysis`, or `release`
+
+## Artifacts
+
+The workflow uploads:
+
+- 📦 APK file
+- 📦 App Bundle (AAB)
+- 🧩 Debug symbols
+- 📊 Size analysis report (optional)
+
+## Pull Request Integration
+
+When using the label:
+
+```
+⚗️ Request Build
+```
+
+- A build is triggered
+- The label is automatically removed
+- A comment with artifact links is posted (via artifact2pr)
+
+## Release Flow
+
+When `build-type: release` and `release-version` is set:
+
+- Updates `pubspec.yaml` version
+- Builds signed artifacts (if secrets available)
+- Commits updated version
+- Creates a **draft GitHub release**
+- Uploads:
+  - APK
+  - AAB
+  - Zipped symbols
+
+## Notes
+
+- Signing is skipped automatically if no keystore is provided.
+- Forked PRs do not have access to secrets → no signing.
+- Artifacts are retained according to GitHub’s default retention policy.
+- The workflow uses concurrency control to cancel outdated runs.
+
+## License
+
+[MIT](LICENSE)