chore: organize solution into module folders (Core/Server/Drivers/Client/Tooling)

Group all 69 projects into category subfolders under src/ and tests/ so the
Rider Solution Explorer mirrors the module structure. Folders: Core, Server,
Drivers (with a nested Driver CLIs subfolder), Client, Tooling.

- Move every project folder on disk with git mv (history preserved as renames).
- Recompute relative paths in 57 .csproj files: cross-category ProjectReferences,
  the lib/ HintPath+None refs in Driver.Historian.Wonderware, and the external
  mxaccessgw refs in Driver.Galaxy and its test project.
- Rebuild ZB.MOM.WW.OtOpcUa.slnx with nested solution folders.
- Re-prefix project paths in functional scripts (e2e, compliance, smoke SQL,
  integration, install).

Build green (0 errors); unit tests pass. Docs left for a separate pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli.Tests/ReadCommandTests.cs

@@ -0,0 +1,21 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli.Commands;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli.Tests;
+
+[Trait("Category", "Unit")]
+public sealed class ReadCommandTests
+{
+    [Theory]
+    [InlineData(ModbusRegion.HoldingRegisters, 100, ModbusDataType.UInt16, "HR[100]:UInt16")]
+    [InlineData(ModbusRegion.Coils, 0, ModbusDataType.Bool, "Coil[0]:Bool")]
+    [InlineData(ModbusRegion.DiscreteInputs, 42, ModbusDataType.Bool, "DI[42]:Bool")]
+    [InlineData(ModbusRegion.InputRegisters, 5, ModbusDataType.Int16, "IR[5]:Int16")]
+    [InlineData(ModbusRegion.HoldingRegisters, 200, ModbusDataType.Float32, "HR[200]:Float32")]
+    public void SynthesiseTagName_produces_stable_region_prefix_plus_address_plus_type(
+        ModbusRegion region, ushort address, ModbusDataType type, string expected)
+    {
+        ReadCommand.SynthesiseTagName(region, address, type).ShouldBe(expected);
+    }
+}