feat(applications): add application detail page

- New page /applications/:id with identity (editable name), associated
  ports (add/remove), linked hosts (read-only via shared ports), and
  delete with confirmation modal
- Add get_application_detail and update_application server functions
- Add ApplicationDetail and HostRef types in api/applications
- Add update_application to the repository layer
- Application names in the list are now clickable links

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

src/api/applications.rs

@@ -5,6 +5,24 @@ use serde::{Deserialize, Serialize};
 
 use crate::models::Application;
 
+// Minimal host reference used by ApplicationDetail.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct HostRef {
+    pub id:   i64,
+    pub name: String,
+    pub ip:   String,
+}
+
+// Full detail for a single application: identity, associated ports, and linked hosts.
+// Linked hosts are those that have at least one port matching an application_ports entry.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct ApplicationDetail {
+    pub id:    i64,
+    pub name:  String,
+    pub ports: Vec<u16>,
+    pub hosts: Vec<HostRef>,
+}
+
 // Application row enriched with the number of hosts that use at least one of
 // its registered ports.  Host count is computed via the join:
 //   application_ports → host_ports (matched on port_number) → hosts
@@ -65,6 +83,52 @@ pub async fn get_applications() -> Result<Vec<Application>, ServerFnError> {
         .map_err(|e| ServerFnError::new(e.to_string()))
 }
 
+/// Returns full detail for a single application: identity, ports, and linked hosts.
+///
+/// Linked hosts are hosts that have at least one open port matching one of
+/// the application's registered port numbers (via application_ports ↔ host_ports).
+#[server]
+pub async fn get_application_detail(id: i64) -> Result<ApplicationDetail, ServerFnError> {
+    use sqlx::{AnyPool, Row};
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    let app = repo::find_application(&pool, id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?
+        .ok_or_else(|| ServerFnError::new(format!("Application {id} not found")))?;
+
+    let ports = repo::list_ports_for_application(&pool, id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    let rows = sqlx::query(
+        "SELECT DISTINCT h.id, h.name, h.ip
+         FROM hosts h
+         JOIN host_ports hp        ON hp.host_id    = h.id
+         JOIN application_ports ap ON ap.port_number = hp.port_number
+         WHERE ap.application_id = $1
+         ORDER BY h.name",
+    )
+    .bind(id)
+    .fetch_all(&pool)
+    .await
+    .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    let hosts = rows
+        .iter()
+        .map(|row| HostRef {
+            id:   row.get("id"),
+            name: row.get("name"),
+            ip:   row.get("ip"),
+        })
+        .collect();
+
+    Ok(ApplicationDetail { id: app.id, name: app.name, ports, hosts })
+}
+
 /// Returns the port numbers associated with an application.
 #[server]
 pub async fn get_ports_for_application(
@@ -83,6 +147,24 @@ pub async fn get_ports_for_application(
 
 // ─── Mutations ────────────────────────────────────────────────────────────────
 
+/// Updates the name of an application and returns the updated record.
+#[server]
+pub async fn update_application(id: i64, name: String) -> Result<Application, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    if name.trim().is_empty() {
+        return Err(ServerFnError::new("Application name cannot be empty"));
+    }
+
+    repo::update_application(&pool, id, name.trim())
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))
+}
+
 /// Creates a new application, then associates the given port numbers.
 ///
 /// `ports` is a comma-separated list of port numbers (e.g. "80,443").

src/app.rs

@@ -12,6 +12,7 @@ use leptos_router::{
 };
 
 use crate::client::{
+    application_detail::ApplicationDetailPage,
     applications::ApplicationsPage,
     home::HomePage,
     host_detail::HostDetailPage,
@@ -115,6 +116,7 @@ pub fn App() -> impl IntoView {
                     <Route path=path!("/hosts") view=HostsPage/>
                     <Route path=path!("/hosts/:id") view=HostDetailPage/>
                     <Route path=path!("/applications") view=ApplicationsPage/>
+                    <Route path=path!("/applications/:id") view=ApplicationDetailPage/>
                 </Routes>
             </main>
         </Router>

src/client/application_detail.rs

@@ -0,0 +1,299 @@
+// client/application_detail.rs — Application detail page
+//
+// Shows all information for a single application:
+//   - Identity form  : name — editable, saved with "Save changes"
+//   - Ports section  : ports associated with this application + Add/Remove per port
+//   - Hosts section  : hosts sharing at least one port with this application (read-only)
+//   - Delete button  : confirmation modal, then navigates back to /applications
+
+use leptos::prelude::*;
+use leptos_router::hooks::{use_navigate, use_params_map};
+
+use crate::api::applications::{
+    AddPortToApplication, DeleteApplication, RemovePortFromApplication,
+    UpdateApplication, get_application_detail,
+};
+
+// ─── Delete confirmation modal ────────────────────────────────────────────────
+
+#[component]
+fn DeleteModal(
+    app_name: String,
+    delete_action: ServerAction<DeleteApplication>,
+    app_id: i64,
+    show_modal: RwSignal<bool>,
+) -> impl IntoView {
+    view! {
+        <div class="modal-backdrop" on:click=move |_| show_modal.set(false)>
+            <div class="modal" on:click=move |e| e.stop_propagation()>
+                <div class="modal__header">
+                    <h2>"Delete application"</h2>
+                    <button class="modal__close" type="button" aria-label="Close"
+                        on:click=move |_| show_modal.set(false)>
+                        "×"
+                    </button>
+                </div>
+                <div class="modal__body">
+                    <p class="warning">
+                        "Are you sure you want to delete "
+                        <strong>{app_name}</strong>
+                        "? All port associations will also be removed."
+                    </p>
+                </div>
+                <div class="modal__actions">
+                    <button class="btn-secondary" type="button"
+                        on:click=move |_| show_modal.set(false)>
+                        "Cancel"
+                    </button>
+                    <button class="btn-danger" type="button"
+                        on:click=move |_| { delete_action.dispatch(DeleteApplication { id: app_id }); }>
+                        "Delete"
+                    </button>
+                </div>
+            </div>
+        </div>
+    }.into_any()
+}
+
+// ─── Main page component ──────────────────────────────────────────────────────
+
+#[component]
+pub fn ApplicationDetailPage() -> impl IntoView {
+    let params = use_params_map();
+    let app_id = move || {
+        params.read().get("id")
+            .and_then(|s| s.parse::<i64>().ok())
+            .unwrap_or(0)
+    };
+
+    let update_action      = ServerAction::<UpdateApplication>::new();
+    let add_port_action    = ServerAction::<AddPortToApplication>::new();
+    let remove_port_action = ServerAction::<RemovePortFromApplication>::new();
+    let delete_action      = ServerAction::<DeleteApplication>::new();
+
+    let show_delete_modal = RwSignal::new(false);
+
+    let app = LocalResource::new(move || {
+        let _ = update_action.version().get();
+        let _ = add_port_action.version().get();
+        let _ = remove_port_action.version().get();
+        get_application_detail(app_id())
+    });
+
+    let name_sig = RwSignal::new(String::new());
+    let new_port = RwSignal::new(String::new());
+
+    // Sync the editable name whenever fresh data arrives.
+    Effect::new(move |_| {
+        if let Some(r) = app.get() {
+            if let Ok(ref detail) = *r {
+                name_sig.set(detail.name.clone());
+            }
+        }
+    });
+
+    let navigate = use_navigate();
+    Effect::new(move |_| {
+        if let Some(Ok(true)) = delete_action.value().get() {
+            navigate("/applications", Default::default());
+        }
+    });
+
+    view! {
+        <div class="application-detail-page">
+            // Delete modal lives OUTSIDE <Suspense> so it is not unmounted when
+            // the application resource re-fetches.
+            {move || show_delete_modal.get().then(|| view! {
+                <DeleteModal
+                    app_name=name_sig.get()
+                    delete_action=delete_action
+                    app_id=app_id()
+                    show_modal=show_delete_modal
+                />
+            })}
+
+            <Suspense fallback=|| view! { <p class="empty">"Loading application…"</p> }>
+                {move || app.get().map(|r| match (*r).clone() {
+                    Err(e) => view! {
+                        <p class="error">"Could not load application: " {e.to_string()}</p>
+                    }.into_any(),
+
+                    Ok(detail) => {
+                        let id         = detail.id;
+                        let port_count = detail.ports.len();
+                        let host_count = detail.hosts.len();
+                        let ports      = detail.ports;
+                        let hosts      = detail.hosts;
+
+                        let ports_list = if ports.is_empty() {
+                            view! {
+                                <p class="empty">"No ports associated with this application."</p>
+                            }.into_any()
+                        } else {
+                            view! {
+                                <div class="port-list">
+                                    {ports.into_iter().map(|num| {
+                                        view! {
+                                            <div class="port-row">
+                                                <span class="port-row__number">{num}</span>
+                                                <button
+                                                    class="btn-danger"
+                                                    type="button"
+                                                    on:click=move |_| {
+                                                        remove_port_action.dispatch(
+                                                            RemovePortFromApplication {
+                                                                application_id: id,
+                                                                port_number: num,
+                                                            }
+                                                        );
+                                                    }
+                                                >
+                                                    "Remove"
+                                                </button>
+                                            </div>
+                                        }
+                                    }).collect_view()}
+                                </div>
+                            }.into_any()
+                        };
+
+                        let hosts_list = if hosts.is_empty() {
+                            view! {
+                                <p class="empty">"No hosts share a port with this application."</p>
+                            }.into_any()
+                        } else {
+                            view! {
+                                <div class="app-list">
+                                    {hosts.into_iter().map(|host| {
+                                        view! {
+                                            <div class="app-row">
+                                                <a class="table-link"
+                                                    href=format!("/hosts/{}", host.id)>
+                                                    {host.name}
+                                                </a>
+                                                <span class="cell-mono">{host.ip}</span>
+                                            </div>
+                                        }
+                                    }).collect_view()}
+                                </div>
+                            }.into_any()
+                        };
+
+                        view! {
+                            // ── Page header ───────────────────────────────────
+                            <div class="page-header detail-page-header">
+                                <a class="back-btn" href="/applications">"← Applications"</a>
+                                <h1 class="detail-page-title">{move || name_sig.get()}</h1>
+                            </div>
+
+                            // ── Identity form ─────────────────────────────────
+                            <section class="detail-section">
+                                <h2 class="detail-section__title">"Identity"</h2>
+                                <div class="detail-form">
+                                    <label class="detail-field">
+                                        "Name"
+                                        <input
+                                            type="text"
+                                            prop:value=move || name_sig.get()
+                                            on:input=move |e| name_sig.set(event_target_value(&e))
+                                        />
+                                    </label>
+
+                                    {move || update_action.value().get()
+                                        .and_then(|r| r.err())
+                                        .map(|e| view! { <p class="error">{e.to_string()}</p> })
+                                    }
+
+                                    <div class="form-actions">
+                                        <button
+                                            class="btn-primary"
+                                            type="button"
+                                            on:click=move |_| {
+                                                update_action.dispatch(UpdateApplication {
+                                                    id,
+                                                    name: name_sig.get_untracked(),
+                                                });
+                                            }
+                                        >
+                                            "Save changes"
+                                        </button>
+                                    </div>
+                                </div>
+                            </section>
+
+                            // ── Ports section ─────────────────────────────────
+                            <section class="detail-section">
+                                <h2 class="detail-section__title">
+                                    {format!("Associated ports ({})", port_count)}
+                                </h2>
+
+                                {ports_list}
+
+                                {move || remove_port_action.value().get()
+                                    .and_then(|r| r.err())
+                                    .map(|e| view! {
+                                        <p class="error">"Remove failed: " {e.to_string()}</p>
+                                    })
+                                }
+
+                                <div class="port-add-row">
+                                    <input
+                                        type="number"
+                                        min="1"
+                                        max="65535"
+                                        placeholder="Port number (1–65535)"
+                                        prop:value=move || new_port.get()
+                                        on:input=move |e| new_port.set(event_target_value(&e))
+                                    />
+                                    <button
+                                        class="btn-primary"
+                                        type="button"
+                                        on:click=move |_| {
+                                            let raw = new_port.get_untracked();
+                                            if let Ok(n) = raw.trim().parse::<i64>() {
+                                                if (1..=65535).contains(&n) {
+                                                    add_port_action.dispatch(AddPortToApplication {
+                                                        application_id: id,
+                                                        port_number: n as u16,
+                                                    });
+                                                    new_port.set(String::new());
+                                                }
+                                            }
+                                        }
+                                    >
+                                        "Add port"
+                                    </button>
+                                    {move || add_port_action.value().get()
+                                        .and_then(|r| r.err())
+                                        .map(|e| view! {
+                                            <p class="error">"Add failed: " {e.to_string()}</p>
+                                        })
+                                    }
+                                </div>
+                            </section>
+
+                            // ── Hosts section (read-only — linked via shared ports) ──
+                            <section class="detail-section">
+                                <h2 class="detail-section__title">
+                                    {format!("Linked hosts ({})", host_count)}
+                                </h2>
+                                {hosts_list}
+                            </section>
+
+                            // ── Danger zone ───────────────────────────────────
+                            <div class="danger-zone">
+                                <button
+                                    class="btn-danger-solid"
+                                    type="button"
+                                    on:click=move |_| show_delete_modal.set(true)
+                                >
+                                    "Delete application"
+                                </button>
+                            </div>
+                        }.into_any()
+                    }
+                })}
+            </Suspense>
+        </div>
+    }.into_any()
+}

src/client/applications.rs

@@ -263,7 +263,12 @@ pub fn ApplicationsPage() -> impl IntoView {
                                                     let app_clone = app.clone();
                                                     view! {
                                                         <tr>
-                                                            <td>{app.name}</td>
+                                                            <td>
+                                                                <a class="table-link"
+                                                                    href=format!("/applications/{}", app.id)>
+                                                                    {app.name}
+                                                                </a>
+                                                            </td>
                                                             <td class="col-count">{app.host_count}</td>
                                                             <td class="col-actions">
                                                                 <button on:click=move |_| {

src/client/mod.rs

@@ -9,6 +9,7 @@
 // Do not place code here that requires browser-only APIs (window, document...)
 // without guarding it with `#[cfg(target_arch = "wasm32")]`.
 
+pub mod application_detail; // Application detail: identity, ports, linked hosts, delete
 pub mod applications;       // Applications list and creation
 pub mod home;               // Home page
 pub mod host_detail;        // Host detail: identity, ports, edit, delete

src/server/repository/applications.rs

@@ -42,6 +42,18 @@ pub async fn create_application(pool: &AnyPool, name: &str) -> Result<Applicatio
     Ok(row_to_application(&row))
 }
 
+/// Updates the name of an application. Returns the updated record.
+pub async fn update_application(pool: &AnyPool, id: i64, name: &str) -> Result<Application, DbError> {
+    let row = sqlx::query(
+        "UPDATE applications SET name = $1 WHERE id = $2 RETURNING id, name",
+    )
+    .bind(name)
+    .bind(id)
+    .fetch_one(pool)
+    .await?;
+    Ok(row_to_application(&row))
+}
+
 /// Deletes an application and its port associations (via `ON DELETE CASCADE`).
 ///
 /// Returns `true` if a row was deleted, `false` if the id did not exist.