docs: Restructure and internationalize documentation

README.md

@@ -1,2 +1,18 @@
-# Home assistant irrigation system
-This is a home assistant irrigation system
+[🇩🇪 Deutsch](README.de.md) | [🇬🇧 English](README.md)
+
+# Modular Irrigation System
+
+This project implements a smart, modular irrigation system controlled via Home Assistant.
+
+## Documentation
+
+The detailed documentation can be found in the [`docs/`](./docs/) directory:
+
+*   **[Concept](./docs/concept.en.md)**: Describes the system architecture, the components used, and the basic design decisions.
+*   **[MODBUS Registers](./docs/modbus-registers.en.md)**: Defines the register map for communication with the slave nodes.
+*   **[Project Plan](./docs/planning.en.md)**: Contains the development and implementation plan.
+
+## Quick Start
+
+*   **Hardware**: The KiCad files for the hardware are located in the [`hardware/`](./hardware/) directory.
+*   **Software**: The Zephyr-based firmware for the slave nodes is located in the [`software/`](./software/) directory.