legal: add AGPL-3.0 license, copyright headers, commercial license info

- LICENSE: GNU AGPL-3.0 (full text)
- Copyright headers added to all 19 source files (TS + Vue)
- COMMERCIAL_LICENSE.md: dual-license explanation (AGPL + commercial)

COMMERCIAL_LICENSE.md

@@ -0,0 +1,33 @@
+# Commercial License
+
+This software is dual-licensed:
+
+1. **GNU AGPL-3.0** — for open-source use, self-hosting, and community contributions
+2. **Commercial License** — for use cases that require avoiding AGPL obligations
+
+## When you need a commercial license
+
+You need a commercial license if your use case involves any of the following and you do not want to release your modifications under AGPL-3.0:
+
+- **Self-hosting a modified version** at a venue or organization (e.g., karting tracks, sim racing centers)
+- **Embedding or bundling** this software into hardware products (e.g., data loggers, OBD-II devices, telemetry hardware)
+- **Offering a modified version as a network service** (the AGPL-3.0 §13 network-use clause requires sharing all modifications if you don't have a commercial license)
+- **Distributing modified versions** without releasing source code
+
+## When you do NOT need a commercial license
+
+- Personal, non-commercial use (e.g., analyzing your own sim racing telemetry)
+- Studying, modifying, or contributing to the open-source project
+- Self-hosting an unmodified version for personal use
+- Any use where you are comfortable releasing modifications under AGPL-3.0
+
+## Contact
+
+For commercial license inquiries, pricing, and terms:
+
+**Jan-Peter v. Hunnius**  
+Email: jan@hunnius.net
+
+## Contributor License Agreement
+
+External contributors must sign a Contributor License Agreement (CLA) before their contributions can be merged. This ensures the project maintainer retains the right to offer commercial licenses. The CLA grants the maintainer a perpetual, worldwide, non-exclusive license to use, modify, and sublicense the contribution under any license.