feat(ebook): improve search UX with grid actions and Enter-to-submit

Add a two-column grid layout for the admin protected-phrases actions
and submit the search form on Enter (Shift+Enter for newline).

python/ebook_search/api/static/style.css

@@ -218,6 +218,11 @@ button:hover {
     margin-bottom: 24px;
 }
 
+.actions-grid {
+    display: grid;
+    grid-template-columns: repeat(2, max-content);
+}
+
 /* Answer + results */
 #results {
     display: block;

python/ebook_search/api/templates/admin.html

@@ -52,7 +52,7 @@ head %}
 </section>
 <section>
   <h2>Protected phrases</h2>
-  <section class="actions">
+  <section class="actions actions-grid">
     <form
       hx-post="/admin/phrases/generate-all"
       hx-target="#admin-status"

python/ebook_search/api/templates/search.html

@@ -7,7 +7,8 @@
     <h1>Search</h1>
     <form class="card" hx-post="/search" hx-target="#results" hx-swap="innerHTML">
         <label for="query">What are you looking for?</label>
-        <textarea id="query" name="query" rows="4" placeholder="Ask a question or paste a passage…" required></textarea>
+        <textarea id="query" name="query" rows="4" placeholder="Ask a question or paste a passage…" required
+            onkeydown="if (event.key === 'Enter' && !event.shiftKey) { event.preventDefault(); this.form.requestSubmit(); }"></textarea>
         <div class="form-row">
             <div class="search-toggles">
                 <label class="check">