Un-collapse connection form + add New Device to nav

The 'Create Connection' form now shows directly when clicking an
unconnected port instead of being hidden inside a <details> element
requiring two clicks. Added a 'New Device' nav link that jumps to
the create form on the overview page.

templates/base.html

@@ -12,6 +12,7 @@
         <a href="/" class="nav-brand">Wireplanner</a>
         <div class="nav-links">
             <a href="/">Overview</a>
+            <a href="/#create-device">New Device</a>
             <a href="/models">Models</a>
             <a href="/wall-sockets">Wall Sockets</a>
         </div>

templates/overview.html

@@ -29,7 +29,7 @@
 
 <section>
 <h2>Devices</h2>
-<div class="grid">
+<div class="grid" id="create-device">
 {{range .Devices}}
 <a href="/devices/{{.ID}}" class="card">
     <strong>{{.Name}}</strong>
@@ -40,7 +40,7 @@
 <div class="empty-state">No devices yet. Create one or add a rack first.</div>
 {{end}}
 </div>
-<details>
+<details id="create-device">
 <summary>Create Device</summary>
 <form method="POST" action="/devices/add">
     <label>Name <input name="name" required></label>