Update media-server: UI polish and bug fixes

- Compact header and footer (reduced padding, margins, font sizes)
- Remove separator borders from header and footer
- Fix color contrast on hover states (white text on accent backgrounds)
- Fix album art not updating on track change (composite cache key)
- Slow vinyl spin animation (4s → 12s)
- Replace Add buttons with dashed-border add-cards
- Fix dialog header text color
- Make theme toggle button transparent

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

media_server/static/index.html

@@ -65,7 +65,7 @@
                 <span class="status-dot" id="status-dot"></span>
                 <span class="version-label" id="version-label"></span>
             </div>
-            <div style="display: flex; align-items: center; gap: 1rem;">
+            <div style="display: flex; align-items: center; gap: 0.5rem;">
                 <button class="theme-toggle" onclick="toggleTheme()" data-i18n-title="player.theme" title="Toggle theme" id="theme-toggle">
                     <svg id="theme-icon-sun" viewBox="0 0 24 24" style="display: none;">
                         <path d="M12 7c-2.76 0-5 2.24-5 5s2.24 5 5 5 5-2.24 5-5-2.24-5-5-5zM2 13h2c.55 0 1-.45 1-1s-.45-1-1-1H2c-.55 0-1 .45-1 1s.45 1 1 1zm18 0h2c.55 0 1-.45 1-1s-.45-1-1-1h-2c-.55 0-1 .45-1 1s.45 1 1 1zM11 2v2c0 .55.45 1 1 1s1-.45 1-1V2c0-.55-.45-1-1-1s-1 .45-1 1zm0 18v2c0 .55.45 1 1 1s1-.45 1-1v-2c0-.55-.45-1-1-1s-1 .45-1 1zM5.99 4.58c-.39-.39-1.03-.39-1.41 0-.39.39-.39 1.03 0 1.41l1.06 1.06c.39.39 1.03.39 1.41 0s.39-1.03 0-1.41L5.99 4.58zm12.37 12.37c-.39-.39-1.03-.39-1.41 0-.39.39-.39 1.03 0 1.41l1.06 1.06c.39.39 1.03.39 1.41 0 .39-.39.39-1.03 0-1.41l-1.06-1.06zm1.06-10.96c.39-.39.39-1.03 0-1.41-.39-.39-1.03-.39-1.41 0l-1.06 1.06c-.39.39-.39 1.03 0 1.41s1.03.39 1.41 0l1.06-1.06zM7.05 18.36c.39-.39.39-1.03 0-1.41-.39-.39-1.03-.39-1.41 0l-1.06 1.06c-.39.39-.39 1.03 0 1.41s1.03.39 1.41 0l1.06-1.06z"/>
@@ -177,8 +177,6 @@
 
         <!-- Media Browser Section -->
         <div class="browser-container" data-tab-content="browser" >
-            <h2 data-i18n="browser.title">Media Browser</h2>
-
             <!-- Breadcrumb Navigation -->
             <div class="breadcrumb" id="breadcrumb"></div>
 
@@ -246,21 +244,19 @@
 
         <!-- Scripts Section (Quick Actions) -->
         <div class="scripts-container" id="scripts-container" data-tab-content="quick-actions" >
-            <h2 data-i18n="scripts.quick_actions">Quick Actions</h2>
             <div class="scripts-grid" id="scripts-grid">
                 <div class="scripts-empty empty-state-illustration">
                     <svg viewBox="0 0 64 64"><path d="M20 8l-8 48"/><path d="M44 8l8 48"/><path d="M10 24h44"/><path d="M8 40h44"/></svg>
                     <p data-i18n="scripts.no_scripts">No scripts configured</p>
                 </div>
+                <div class="script-btn add-card-grid" onclick="showAddScriptDialog()">
+                    <span class="add-card-icon">+</span>
+                </div>
             </div>
         </div>
 
         <!-- Script Management Section -->
         <div class="script-management" data-tab-content="scripts" >
-            <div class="script-management-header">
-                <h2 data-i18n="scripts.management">Script Management</h2>
-                <button class="add-script-btn" onclick="showAddScriptDialog()" data-i18n="scripts.add">+ Add</button>
-            </div>
             <table class="scripts-table">
                 <thead>
                     <tr>
@@ -282,14 +278,13 @@
                     </tr>
                 </tbody>
             </table>
+            <div class="add-card" onclick="showAddScriptDialog()">
+                <span class="add-card-icon">+</span>
+            </div>
         </div>
 
         <!-- Callback Management Section -->
         <div class="script-management" id="callbacksSection" data-tab-content="callbacks" >
-            <div class="script-management-header">
-                <h2 data-i18n="callbacks.management">Callback Management</h2>
-                <button class="add-script-btn" onclick="showAddCallbackDialog()" data-i18n="callbacks.add">+ Add</button>
-            </div>
             <p style="color: var(--text-secondary); font-size: 0.875rem; margin-bottom: 1rem;" data-i18n="callbacks.description">
                 Callbacks are scripts triggered automatically by media control events (play, pause, stop, etc.)
             </p>
@@ -313,6 +308,9 @@
                     </tr>
                 </tbody>
             </table>
+            <div class="add-card" onclick="showAddCallbackDialog()">
+                <span class="add-card-icon">+</span>
+            </div>
         </div>
     </div>