Harden auto-sync history row rendering

Normalize sparse playlist pipeline history rows before rendering and add a visible fallback for empty entries so the Run History tab cannot collapse into unreadable divider lines.

webui/static/auto-sync.js

@@ -438,13 +438,14 @@ function renderAutoSyncHistoryPanel(history, total) {
             <button onclick="refreshAutoSyncScheduleModal()">Refresh</button>
         </div>
         <div class="auto-sync-history-list">
-            ${history.map(autoSyncHistoryEntryHtml).join('')}
+            ${history.map((entry, index) => autoSyncHistoryEntryHtml(entry, index)).join('')}
             ${total > history.length ? `<div class="auto-sync-history-total">Showing ${history.length} of ${total} runs</div>` : ''}
         </div>
     `;
 }
 
-function autoSyncHistoryEntryHtml(entry) {
+function autoSyncHistoryEntryHtml(entry, index = 0) {
+    entry = autoSyncNormalizeHistoryEntry(entry, index);
     const status = entry.status || 'completed';
     const before = entry.before_json || {};
     const after = entry.after_json || {};
@@ -499,6 +500,40 @@ function autoSyncHistoryEntryHtml(entry) {
     `;
 }
 
+function autoSyncNormalizeHistoryEntry(entry, index) {
+    if (!entry || typeof entry !== 'object') {
+        return {
+            id: `unknown-${index}`,
+            status: 'completed',
+            playlist_name: 'Playlist pipeline run',
+            trigger_source: 'pipeline',
+            summary: 'Run history entry did not include detailed metadata.',
+            before_json: {},
+            after_json: {},
+            result_json: {},
+        };
+    }
+    return {
+        ...entry,
+        id: entry.id ?? `history-${index}`,
+        before_json: autoSyncParseHistoryObject(entry.before_json),
+        after_json: autoSyncParseHistoryObject(entry.after_json),
+        result_json: autoSyncParseHistoryObject(entry.result_json),
+    };
+}
+
+function autoSyncParseHistoryObject(value) {
+    if (!value) return {};
+    if (typeof value === 'object') return value;
+    if (typeof value !== 'string') return {};
+    try {
+        const parsed = JSON.parse(value);
+        return parsed && typeof parsed === 'object' ? parsed : {};
+    } catch (_err) {
+        return {};
+    }
+}
+
 function autoSyncHistoryFallbackSummary(before, after, status) {
     const beforeTracks = parseInt(before.track_count, 10) || 0;
     const afterTracks = parseInt(after.track_count, 10) || 0;

webui/static/style.css

@@ -12023,6 +12023,8 @@ body.helper-mode-active #dashboard-activity-feed:hover {
 }
 
 .auto-sync-history-entry {
+    display: block;
+    min-height: 84px;
     border: 1px solid rgba(255, 255, 255, 0.1);
     border-radius: 10px;
     background:
@@ -12032,6 +12034,19 @@ body.helper-mode-active #dashboard-activity-feed:hover {
     box-shadow: 0 10px 26px rgba(0, 0, 0, 0.14);
 }
 
+.auto-sync-history-entry:empty {
+    display: flex;
+    align-items: center;
+    padding: 16px;
+}
+
+.auto-sync-history-entry:empty::before {
+    content: 'Run history entry unavailable. Refresh after the next playlist pipeline run.';
+    color: rgba(255, 255, 255, 0.58);
+    font-size: 12px;
+    font-weight: 700;
+}
+
 .auto-sync-history-entry:hover {
     border-color: rgba(var(--accent-rgb), 0.3);
     background:
@@ -12047,6 +12062,7 @@ body.helper-mode-active #dashboard-activity-feed:hover {
     min-height: 84px;
     padding: 15px 16px;
     cursor: pointer;
+    background: rgba(255, 255, 255, 0.018);
 }
 
 .auto-sync-history-status {