Extract PowerDisplay.Models to decouple Settings.UI from PowerDisplay…

[moooyo]

….Lib

• Create PowerDisplay.Models project with shared model types (ColorPresetItem, CustomVcpValueMapping, PowerDisplayProfile, PowerDisplayProfiles, ProfileMonitorSetting) and ProfileHelper/ProfileSerializationContext
• Remove Settings.UI and Settings.UI.Library dependency on PowerDisplay.Lib
• Clean up VcpNames: remove LocalizedCodeNameProvider, GetValueMappings, GetFormattedValueName with custom mapping overload (keep 4 methods)
• Refactor ProfileService: delegate Load/Save to ProfileHelper, remove unused methods (ProfilesFileExists, GetProfilesFilePath), simplify IProfileService interface
• Remove legacy CustomProfileName constant and cleanup code
• Add CustomVcpValueMappingExtensions in Lib for rich display properties
• Create MonitorStateSerializationContext for Lib-local state types

Summary of the Pull Request

PR Checklist

• Closes: #xxx

• Communication: I've discussed this with core contributors already. If the work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end-user-facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed