docs: CONTRIBUTING.md hinzufügen (Fork-Flow, Branch-Modell, Commit-Stil)

CONTRIBUTING.md

@@ -0,0 +1,102 @@
+# Contributing to KX-Bridge
+
+Thanks for taking the time to contribute! Here's everything you need to know.
+
+---
+
+## How to report a bug or request a feature
+
+Use the issue tracker:
+
+- **Bug:** [New Bug Report](https://gitea.it-drui.de/viewit/KX-Bridge-Release/issues/new?template=bug_report.md)
+- **Feature:** [New Feature Request](https://gitea.it-drui.de/viewit/KX-Bridge-Release/issues/new?template=feature_request.md)
+
+Please fill in the template — especially the **KX-Bridge version** and **logs**.  
+Issues without version info are hard to debug.
+
+---
+
+## How to submit a Pull Request
+
+### 1. Fork the repository
+
+Click **Fork** at the top of this page.  
+You now have your own copy at `gitea.it-drui.de/your-username/KX-Bridge-Release`.
+
+### 2. Clone your fork
+
+```bash
+git clone https://gitea.it-drui.de/your-username/KX-Bridge-Release.git
+cd KX-Bridge-Release
+```
+
+### 3. Create a branch
+
+Always branch off `nightly`:
+
+```bash
+git checkout nightly
+git checkout -b feature/my-feature   # or fix/my-fix
+```
+
+### 4. Make your changes
+
+- Test your changes locally with Docker:
+  ```bash
+  docker build -t kx-bridge:dev .
+  docker run -p 7125:7125 -v ./config:/app/config kx-bridge:dev
+  ```
+- No debug `print()` statements — use `logging`
+- Keep commits focused; one thing per commit
+
+### 5. Push and open a PR
+
+```bash
+git push origin feature/my-feature
+```
+
+Gitea will show a banner — click **"Create Pull Request"**.  
+The PR template will be pre-filled. Set the target branch to **`nightly`**.
+
+---
+
+## Branch model
+
+```
+main      ← stable releases only (merged by maintainer)
+nightly   ← integration branch — PRs go here
+feature/* ← your feature branch (in your fork)
+fix/*     ← your bugfix branch (in your fork)
+```
+
+Your PR always targets `nightly`. The maintainer periodically merges `nightly → main` for a new stable release.
+
+---
+
+## Commit style
+
+Use conventional commit prefixes:
+
+| Prefix | When |
+|---|---|
+| `feat:` | new feature |
+| `fix:` | bug fix |
+| `docs:` | documentation only |
+| `chore:` | maintenance, dependencies |
+| `refactor:` | code change without new feature or fix |
+
+Example: `fix: prevent crash when printer is offline during startup`
+
+---
+
+## Language
+
+- **Code and comments:** English
+- **Issue comments:** match the language of the issue (if someone writes in German, reply in German)
+- **Commit messages:** English
+
+---
+
+## Questions?
+
+Open a [Discussion](https://gitea.it-drui.de/viewit/KX-Bridge-Release/issues) or leave a comment on the relevant issue.