feat(networks): add name field to networks

- Migration 0007: ALTER TABLE networks ADD COLUMN name TEXT NOT NULL DEFAULT ''
- Network model, repository, and API updated to include name
- Networks page: name input in the add form, Name column as first column in table
- Delete modal now shows "Name (CIDR)" for clarity
- Hosts page: network dropdowns now show network name instead of CIDR
- Seeds updated with names (LAN, DMZ, Corporate, VPN)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/client/hosts.rs

@@ -74,7 +74,7 @@ fn AddHostModal(
                                 {move || networks_res.get()
                                     .and_then(|r| r.ok())
                                     .map(|nets| nets.into_iter().map(|n| {
-                                        view! { <option value=n.id.to_string()>{n.cidr}</option> }
+                                        view! { <option value=n.id.to_string()>{n.name}</option> }
                                     }).collect_view())
                                 }
                             </select>
@@ -137,7 +137,7 @@ fn FilterBar(
                         {move || networks_res.get()
                             .and_then(|r| r.ok())
                             .map(|nets| nets.into_iter().map(|n| {
-                                view! { <option value=n.id.to_string()>{n.cidr}</option> }
+                                view! { <option value=n.id.to_string()>{n.name}</option> }
                             }).collect_view())
                         }
                     </select>