perf fix + ad guard for the games grid, search section cleanup

- drop backdrop-filter from .game tiles (likely cause of a freeze-on-load
  bug on heavy uncached loads) and harden tile sizing so it can't balloon
  regardless; fix some long-dead CSS selectors along the way (mobile
  breakpoints were silently never applying)
- strip AdSense in-feed ads if they try to inject into the games grid
- top games / starred / recently played now only show a section if
  something inside it still matches the current search or tag filter,
  instead of leaving orphaned tiles with no header or stale clutter
- remove the proxy nav card from home (dead now that it's disabled)
- delete cookie.js and savedownload.js, confirmed fully unreferenced
  dead code superseded by the save/load flow already in settings.html

home.html

@@ -61,13 +61,6 @@
 				})
 				.catch((error) => console.error("Error loading quotes:", error));
 
-			fetch("/api/proxy/status")
-				.then((res) => res.json())
-				.then((data) => {
-					if (data.unlocked) document.getElementById("proxyNavCard").style.display = "";
-				})
-				.catch(() => { });
-
 			document.getElementById("openblank").addEventListener("click", (e) => {
 				e.preventDefault();
 				let win = window.open();
@@ -102,10 +95,6 @@
 			<img src="img/apps.svg" />
 			<span>apps</span>
 		</a>
-		<a class="navCard" href="proxy.html" id="proxyNavCard" style="display: none;">
-			<img src="img/addlink.svg" />
-			<span>proxy</span>
-		</a>
 		<a class="navCard" href="bookmarklets.html">
 			<img src="img/bookmarklets.svg" />
 			<span>bookmarklets</span>