Redesign the Hosts page around source-aware grouped rows with shared table shell styling, fix effective-config save session synchronization, and move read-ethers into the DHCP model where dnsmasq actually applies it.
- EffectiveConfigFieldRef as value type; PendingDnsmasqChange/PendingOptionChange/PendingManagedHostsChange
- Multi-file save plan (DnsmasqSaveWritePlan, DnsmasqManagedBackup) and backup/restore in save flow
- Hosts integrated into effective-config save; Hosts.razor uses shared save modal
- IEffectiveConfigDescriptorProvider + IEffectiveConfigFieldBuilder (DI); descriptors from EffectiveConfigSections
- IEffectiveConfigPageEditor, shared descriptor resolution; addn-hosts/dhcp-host descriptor fix
- DnsmasqConfText, IEffectiveConfigDirectiveSerializer; DnsmasqConfigService uses serializer for writes
- IStructuredOptionValueHandler/Registry, DhcpHostOptionValueHandler; Dhcp.razor index-based DeleteRow fix
- SaveService: roll back partial writes on failure; SaveModal: WriteFailed shows backups and Restore button
- Move Client/Http, Services, Parsers under Infrastructure/ (Client, Services, Parsers)
- Move config helpers (DnsmasqConfKeys, DnsmasqOptionTooltips, DnsmasqFileEncoding, EffectiveConfigFieldBuilder) to Infrastructure/Helpers/Config; ApiJsonOptions to Helpers/Http
- Move Configuration types (ApplicationOptions, DnsmasqOptions, DnsmasqOptionsValidator) to Models/Config
- Merge Models/Status and Models/EffectiveConfig into Models/Dnsmasq and Models/Dnsmasq/EffectiveConfig
- Move Client/Models and Client/Services to Models/Client and Infrastructure/Services
- Move ConfigSetSnapshot, HostsSnapshot, ProcessRunResult, ManagedConfigContent from Infrastructure/Services/Abstractions to Models/Contracts
- Update all namespaces and usings; tests pass
alex