Fix search dropdown, async artist add, OOB swaps

- Fix search results dropdown: absolute position relative to search wrapper
- Make release group fetching async via Vert.x executeBlocking (avoid blocking add)
- Add OOB swap for artist list so +Add works from any page
- Simplify search-results template styling
- Add Response type for combined OOB responses

src/main/resources/templates/layouts/base.html

@@ -7,12 +7,16 @@
   <link href="https://cdn.jsdelivr.net/npm/daisyui@4.12.23/dist/full.min.css" rel="stylesheet">
   <script src="https://unpkg.com/htmx.org@2.0.4/dist/htmx.min.js"></script>
   <style>
-    .search-dropdown {
+    #search-wrapper {
+      position: relative;
+    }
+    #search-results {
       position: absolute;
       top: 100%;
       left: 0;
       right: 0;
       z-index: 50;
+      width: 100%;
     }
   </style>
   <script>
@@ -40,7 +44,7 @@
     </div>
 
     <div class="navbar-center">
-      <div class="relative">
+      <div id="search-wrapper" class="w-48 md:w-64">
         <form hx-get="/api/artists/search"
               hx-target="#search-results"
               hx-swap="innerHTML"
@@ -48,18 +52,18 @@
           <input id="search-input"
                  type="text"
                  placeholder="Search artists..."
-                 class="input input-bordered input-sm w-48 md:w-64"
+                 class="input input-bordered input-sm w-full"
                  name="q"
                  autocomplete="off">
         </form>
-        <div id="search-results" class="search-dropdown"></div>
+        <div id="search-results"></div>
       </div>
     </div>
 
     <div class="navbar-end gap-2">
       <select class="select select-bordered select-sm w-full max-w-[8rem]"
               onchange="setTheme(this)">
-        <option value="dark">Dark</option>
+        <option value="dark" selected>Dark</option>
         <option value="light">Light</option>
         <option value="synthwave">Synthwave</option>
         <option value="retro">Retro</option>