feat(hosts): replace inline add form with modal dialog

The add-host form is now opened via a "+ Add host" button in the page
header. The modal closes on Cancel, backdrop click, × button, or
automatically after a successful creation.

Adds modal CSS with backdrop blur and entry animation, .btn-primary /
.btn-secondary shared button styles, and a .page-header flex layout
reusable across list pages.

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

src/client/hosts.rs

@@ -1,15 +1,14 @@
 // client/hosts.rs — Hosts list page
 //
 // Displays all hosts across every network with:
-//   - Add form    : create a host inside a chosen network
-//   - Filter bar  : name (substring), network, open port, application
-//   - Table       : name, IP, network, port count, application count, delete
-//   - Pagination  : configurable page size (15 / 25 / 50 / 100 / All)
+//   - Add button   : opens a modal form to create a host inside a chosen network
+//   - Filter bar   : name (substring), network, open port, application
+//   - Table        : name, IP, network, port count, application count, delete
+//   - Pagination   : configurable page size (15 / 25 / 50 / 100 / All)
 //
-// Each sub-component calls `.into_any()` on its view to return `AnyView`
-// (a type-erased wrapper). This prevents Rust from composing all the nested
-// generic types into a single enormous type in the parent's monomorphization,
-// which would otherwise overflow the compiler's query depth limit.
+// Sub-components call `.into_any()` on their views to erase the concrete
+// Leptos type, preventing the parent from accumulating a deeply-nested
+// generic type that overflows the compiler's query depth limit.
 
 use leptos::prelude::*;
 use leptos::form::ActionForm;
@@ -28,46 +27,76 @@ const PER_PAGE_OPTIONS: &[(i64, &str)] = &[
     (0,   "All"),
 ];
 
-// ─── Add host form ────────────────────────────────────────────────────────────
+// ─── Add host modal ───────────────────────────────────────────────────────────
 
 #[component]
-fn AddHostForm(
+fn AddHostModal(
     create_action: ServerAction<CreateHost>,
     networks_res: Resource<Result<Vec<crate::models::Network>, ServerFnError>>,
+    show_modal: RwSignal<bool>,
 ) -> impl IntoView {
+    // Close the modal automatically after a successful creation.
+    Effect::new(move |_| {
+        if let Some(Ok(_)) = create_action.value().get() {
+            show_modal.set(false);
+        }
+    });
+
     view! {
-        <section class="add-form">
-            <h2>"Add a host"</h2>
-            <ActionForm action=create_action>
-                <div class="add-form__fields">
-                    <label>
-                        "Name"
-                        <input type="text" name="name" placeholder="e.g. web-server-01" required/>
-                    </label>
-                    <label>
-                        "IP address"
-                        <input type="text" name="ip" placeholder="e.g. 192.168.1.10" required/>
-                    </label>
-                    <label>
-                        "Network"
-                        <select name="network_id" required>
-                            <option value="">"— choose —"</option>
-                            {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> }
-                                }).collect_view())
-                            }
-                        </select>
-                    </label>
-                    <button type="submit">"Add"</button>
+        // Backdrop — click outside the card to close
+        <div class="modal-backdrop" on:click=move |_| show_modal.set(false)>
+            // stop_propagation keeps clicks inside the card from closing the modal
+            <div class="modal" on:click=move |e| e.stop_propagation()>
+                <div class="modal__header">
+                    <h2>"Add a host"</h2>
+                    <button
+                        class="modal__close"
+                        type="button"
+                        aria-label="Close"
+                        on:click=move |_| show_modal.set(false)
+                    >"×"</button>
                 </div>
-            </ActionForm>
-            {move || create_action.value().get()
-                .and_then(|r| r.err())
-                .map(|e| view! { <p class="error">{e.to_string()}</p> })
-            }
-        </section>
+
+                <ActionForm action=create_action>
+                    <div class="add-form__fields">
+                        <label>
+                            "Name"
+                            <input type="text" name="name" placeholder="e.g. web-server-01" required/>
+                        </label>
+                        <label>
+                            "IP address"
+                            <input type="text" name="ip" placeholder="e.g. 192.168.1.10" required/>
+                        </label>
+                        <label>
+                            "Network"
+                            <select name="network_id" required>
+                                <option value="">"— choose —"</option>
+                                {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> }
+                                    }).collect_view())
+                                }
+                            </select>
+                        </label>
+                    </div>
+
+                    <div class="modal__actions">
+                        <button
+                            class="btn-secondary"
+                            type="button"
+                            on:click=move |_| show_modal.set(false)
+                        >"Cancel"</button>
+                        <button type="submit">"Add host"</button>
+                    </div>
+                </ActionForm>
+
+                {move || create_action.value().get()
+                    .and_then(|r| r.err())
+                    .map(|e| view! { <p class="error">{e.to_string()}</p> })
+                }
+            </div>
+        </div>
     }.into_any()
 }
 
@@ -194,7 +223,7 @@ fn PaginationBar(
                             {move || format!("Page {} of {}", page.get(), total_pages.get().max(1))}
                         </span>
                         <button
-                            disabled=move || page.get() >= total_pages.get()
+                            disabled={move || page.get() >= total_pages.get()}
                             on:click=move |_| {
                                 let max = total_pages.get_untracked();
                                 page.update(|p| *p = (*p + 1).min(max));
@@ -209,7 +238,6 @@ fn PaginationBar(
 
 // ─── Host table ───────────────────────────────────────────────────────────────
 
-// Separate component for the table body to further reduce type depth in HostsPage.
 #[component]
 fn HostTable(
     hosts: Resource<Result<HostsPageData, ServerFnError>>,
@@ -284,6 +312,9 @@ pub fn HostsPage() -> impl IntoView {
     let create_action = ServerAction::<CreateHost>::new();
     let delete_action = ServerAction::<DeleteHost>::new();
 
+    // Controls the add-host modal
+    let show_modal = RwSignal::new(false);
+
     // Filter signals (0 / "" = no filter)
     let name_filter       = RwSignal::new(String::new());
     let network_id_filter = RwSignal::new(0i64);
@@ -323,9 +354,21 @@ pub fn HostsPage() -> impl IntoView {
 
     view! {
         <div class="hosts-page">
-            <h1>"Hosts"</h1>
+            <div class="page-header">
+                <h1>"Hosts"</h1>
+                <button class="btn-primary" on:click=move |_| show_modal.set(true)>
+                    "+ Add host"
+                </button>
+            </div>
 
-            <AddHostForm create_action=create_action networks_res=networks_res/>
+            // Modal — only rendered when show_modal is true
+            {move || show_modal.get().then(|| view! {
+                <AddHostModal
+                    create_action=create_action
+                    networks_res=networks_res
+                    show_modal=show_modal
+                />
+            })}
 
             <FilterBar
                 networks_res=networks_res