feat(applications): add ports field to create application form

The add-application modal now accepts a comma-separated list of port
numbers (same UX as the add-host form). Ports are associated with the
new application atomically in create_application on the server side.

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

src/client/applications.rs

@@ -65,6 +65,15 @@ fn AddApplicationModal(
                                 required
                             />
                         </label>
+                        <label>
+                            "Associated ports"
+                            <input
+                                type="text"
+                                name="ports"
+                                placeholder="e.g. 22, 80, 443"
+                            />
+                            <span class="field-hint">"Comma-separated port numbers"</span>
+                        </label>
                     </div>
 
                     <div class="modal__actions">