b0046d6959
MTConnectTagConfigModel: pure FromJson/ToJson/Validate for the MTConnect tag TagConfig JSON blob, mirroring ModbusTagConfigModel/OpcUaClientTagConfigModel. Fields: fullName (DataItem@id, required), dataType (DriverDataType override, written as an enum name string), mtCategory/mtType/mtSubType/units (probe metadata), mtDevice/mtComponent (author context). Preserves unknown JSON keys across load->save (isHistorized/historianTagname and anything else). Guards against the enum-serialization trap (numeric dataType would fault the driver at deploy) both on write (always TagConfigJson.Set via enum name) and on read (Validate() rejects a dataType that was stored as a bare digit string, since Enum.TryParse silently accepts numeric text). AdminUI.csproj gains a ProjectReference to Driver.MTConnect.Contracts, matching the existing POCO-only driver-Contracts pattern used by the other six typed tag editors. Scope: pure model only (Task 17). The razor editor shell + TagConfigEditorMap/ TagConfigValidator registration is Task 18.