fix(dashcam): remove inline width from thumb td, control via CSS with !important

Inline style.width on td was overriding the mobile media query width rule.
Use dash-thumb-td class for desktop (9rem) and mobile (5rem !important).

Co-authored-by: Copilot <[email protected]>

static/js/local-videos.js

@@ -100,8 +100,7 @@
 
             // Thumbnail cell — also contains filename for mobile view
             const preview = document.createElement("td");
-            preview.style.width = "9rem";
-            preview.style.padding = "0.25rem";
+            preview.className = "dash-thumb-td";
             const image = document.createElement("img");
             image.className = "local-video-thumbnail";
             image.alt = "";