feat: consistent compact density across all list views

- Reduce capture-item, files table, date group labels to 6px 12px padding
- Set font-size 0.80rem on capture-text, file table cells

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

static/style.css

@@ -793,8 +793,8 @@ a:hover { color: var(--accent-hover); }
 .capture-item {
     display: flex;
     align-items: flex-start;
-    gap: 12px;
-    padding: 12px;
+    gap: 8px;
+    padding: 6px 12px;
     background: var(--surface);
     border: 1px solid var(--border);
     border-radius: var(--radius);
@@ -803,7 +803,7 @@ a:hover { color: var(--accent-hover); }
 
 .capture-text {
     flex: 1;
-    font-size: 0.92rem;
+    font-size: 0.80rem;
 }
 
 .capture-actions {