Web: reorder stats dashboard cards (Radio+Packets, Wi-Fi+Memory)

Swap Memory and Packets cards in the stats dashboard grid so that
Radio and Packets appear together in the middle row, and Wi-Fi and
Memory appear together in the lower row. This groups network-related
stats (Radio/Packets) and puts the less-frequently-needed Memory card
last, improving readability on both desktop and mobile layouts.

src/helpers/web/WebPanelServer.cpp

@@ -1551,11 +1551,11 @@ const char kWebPanelAppHtml[] PROGMEM = R"HTML(
       ];
       const middleCards = [
         results.radio ? renderRadioCard(results.radio) : renderMissingCard("Radio", "stats-radio unavailable"),
-        results.memory ? renderMemoryCard(results.memory) : renderMissingCard("Memory", "memory unavailable")
+        results.packets ? renderPacketsCard(results.packets) : renderMissingCard("Packets", "stats-packets unavailable")
       ];
       const lowerCards = [
         results.wifi ? renderWifiCard(results.wifi, results.wifi_powersave) : renderMissingCard("Wi-Fi", "wifi.status unavailable"),
-        results.packets ? renderPacketsCard(results.packets) : renderMissingCard("Packets", "stats-packets unavailable")
+        results.memory ? renderMemoryCard(results.memory) : renderMissingCard("Memory", "memory unavailable")
       ];
       dashboardEl.innerHTML = notices +
         `<div class="hud-grid-1">${coreCards.join("")}</div>` +