Doc: finalize server/simulator documentation convergence.

Author: FedericoMusa

doc/source/server.rst

@@ -27,5 +27,9 @@ applications to use the server as if it was synchronous.
 
 Datastore for server
 --------------------
+.. note::
+   The legacy datastores have been replaced by a unified DataModel based on 
+   the Simulator engine. This ensures consistent data handling across all 
+   server types.
 
 :ref:`Datastore definitions`

doc/source/simulator3.rst

@@ -3,18 +3,15 @@ Simulator (3.x)
 
 .. warning:: Beginning with v3.9.0 and ending with v4.0.0 this simulator will be removed by a new version.
 
-The simulator is a full fledged modbus simulator, which is
-constantly being evolved with user ideas / amendments.
+**REMARK**: The core logic of the simulator (SimDevice/SimData) has been integrated into the base server as the unified DataModel. 
 
-The purpose of the simulator is to provide support for client
-application test harnesses with end-to-end testing simulating real life
-modbus devices.
+The purpose of this integration is to provide a single, robust way to handle modbus registers for both standard servers and simulation environments.
 
-The datastore simulator allows the user to (all automated)
+The unified datamodel allows the user to:
 
-- simulate a modbus device by adding a simple configuration,
-- test how a client handles modbus exceptions,
-- test a client apps correct use of the simulated device.
+- Define a modbus device using the new ``SimDevice`` architecture.
+- Handle data using ``SimData`` with specific ``DataType`` (Registers, Coils, etc.).
+- Ensure consistency between simulation and real-world server deployment.
 
 The web interface allows the user to (online / manual)