Dnsmasq/Hosts UI tweaks, test harness: down before redeploy, exclude leases from mount

- Dnsmasq page: Config (Main config, Managed file, Config set) under Service configuration; remove Paths/Leases (in Effective config DHCP); EffectiveConfigSection collapsible groups; StatusSection flex-wrap
- Hosts: HostsFileSection always shows table; 'No host entries' in tbody when empty
- Models: reorganize into sub-namespaces (Config, EffectiveConfig, Hosts, Dhcp, Status); move EffectiveConfig/Status/Logs components under Dnsmasq
- Test harness: prepare-test-mount.sh runs 'docker compose down' before mount+up so all containers (including DHCP clients) restart; exclude testdata/leases from sync (unit tests only); testdata/README

src/DnsmasqWebUI/Client/Http/Abstractions/IConfigSetClient.cs

@@ -1,4 +1,4 @@
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.EffectiveConfig;
 
 namespace DnsmasqWebUI.Client.Http.Abstractions;
 

src/DnsmasqWebUI/Client/Http/Abstractions/IDhcpHostsClient.cs

@@ -1,4 +1,5 @@
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.Dhcp;
+using DnsmasqWebUI.Models.Status;
 
 namespace DnsmasqWebUI.Client.Http.Abstractions;
 

src/DnsmasqWebUI/Client/Http/Abstractions/IHostsClient.cs

@@ -1,4 +1,5 @@
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.Hosts;
+using DnsmasqWebUI.Models.Status;
 
 namespace DnsmasqWebUI.Client.Http.Abstractions;
 

src/DnsmasqWebUI/Client/Http/Abstractions/ILeasesClient.cs

@@ -1,4 +1,4 @@
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.Dhcp;
 
 namespace DnsmasqWebUI.Client.Http.Abstractions;
 

src/DnsmasqWebUI/Client/Http/Abstractions/IStatusClient.cs

@@ -1,4 +1,4 @@
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.Status;
 
 namespace DnsmasqWebUI.Client.Http.Abstractions;
 

src/DnsmasqWebUI/Client/Http/ConfigSetClient.cs

@@ -1,5 +1,5 @@
 using DnsmasqWebUI.Client.Http.Abstractions;
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.EffectiveConfig;
 using System.Net.Http.Json;
 
 namespace DnsmasqWebUI.Client.Http;

src/DnsmasqWebUI/Client/Http/DhcpHostsClient.cs

@@ -1,7 +1,8 @@
 using System.Net.Http.Json;
 using System.Text.Json.Serialization;
 using DnsmasqWebUI.Client.Http.Abstractions;
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.Dhcp;
+using DnsmasqWebUI.Models.Status;
 
 namespace DnsmasqWebUI.Client.Http;
 

src/DnsmasqWebUI/Client/Http/HostsClient.cs

@@ -1,5 +1,6 @@
 using DnsmasqWebUI.Client.Http.Abstractions;
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.Hosts;
+using DnsmasqWebUI.Models.Status;
 using System.Net.Http.Json;
 
 namespace DnsmasqWebUI.Client.Http;

src/DnsmasqWebUI/Client/Http/LeasesClient.cs

@@ -1,5 +1,5 @@
 using DnsmasqWebUI.Client.Http.Abstractions;
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.Dhcp;
 using System.Net.Http.Json;
 
 namespace DnsmasqWebUI.Client.Http;

src/DnsmasqWebUI/Client/Http/StatusClient.cs

@@ -1,6 +1,6 @@
 using System.Text.Json;
 using DnsmasqWebUI.Client.Http.Abstractions;
-using DnsmasqWebUI.Models;
+using DnsmasqWebUI.Models.Status;
 using System.Net.Http.Json;
 
 namespace DnsmasqWebUI.Client.Http;