refactor(driver-s7): extract S7DriverOptions to .Contracts with parallel CpuType enum

Introduces Driver.S7.Contracts (dependency-free POCO project) and moves
S7DriverOptions / S7ProbeOptions / S7TagDefinition / S7DataType into it.
Adds S7CpuType enum mirroring S7.Net.CpuType exactly (7 values with
explicit integer codes). Runtime S7CpuTypeMap bridges S7CpuType →
S7.Net.CpuType at the single Plc construction site in S7Driver.InitializeAsync.
S7DriverFactoryExtensions and S7CommandBase updated to use S7CpuType; test
files updated to match (S7_1500Profile, S7DriverScaffoldTests). AdminUI can
now reference Driver.S7.Contracts without pulling in S7netplus.

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7/S7DriverFactoryExtensions.cs

@@ -1,7 +1,6 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using ZB.MOM.WW.OtOpcUa.Core.Hosting;
-using S7NetCpuType = global::S7.Net.CpuType;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.S7;
 
@@ -60,8 +59,8 @@ public static class S7DriverFactoryExtensions
         {
             Host = dto.Host!,
             Port = dto.Port ?? 102,
-            CpuType = ParseEnum<S7NetCpuType>(dto.CpuType, driverInstanceId, "CpuType",
-                fallback: S7NetCpuType.S71500),
+            CpuType = ParseEnum<S7CpuType>(dto.CpuType, driverInstanceId, "CpuType",
+                fallback: S7CpuType.S71500),
             Rack = dto.Rack ?? 0,
             Slot = dto.Slot ?? 0,
             Timeout = TimeSpan.FromMilliseconds(dto.TimeoutMs ?? 5_000),