error handling docs added

docs/general/Architecture/ErrorHandling.md

+# Error Handling
+
+---
+
+Any error that occurs in the Redux thunk is caught by the appropriate function (rejectWithValue). This function then passes the error message to the middleware (error.middleware.ts), which triggers a show toast with the error content.
+
+Each thunk has a separate try/catch that catches and processes errors in it. It is very important to keep this in mind when modifying thunks or adding new ones. Errors are not automatically caught.
+
+If an error occurs somewhere outside of thunks, use the showToast function directly with the parameter type: error to show a message with the appropriate content. Currently, errors are not clustered in any way with a single function or any other type of algorithm.
+
+![][image1]  
+**Example:** Error parsed to error message and then handled by rejectWithValue
+
+![][image2]  
+**Example:** Thunk error middleware
+
+##### References
+
+- [https://redux.js.org/usage/writing-logic-thunks](https://redux.js.org/usage/writing-logic-thunks)
+- [https://redux-toolkit.js.org/api/createAsyncThunk](https://redux-toolkit.js.org/api/createAsyncThunk)
+
+[image1]: ErrorHandling1.png
+[image2]: ErrorHandling2.png