refactor: rename player thumbnail module to metadata

static/player/episodes/metadata.ts

@@ -0,0 +1,31 @@
+import { state } from "../state";
+
+/** Fetches episode metadata from API and updates episode-card titles. */
+export const setupEpisodeMetadata = (): void => {
+  const { episodeList } = state.elements;
+  if (!episodeList) {
+    return;
+  }
+
+  fetch(`/api/watch/episodes/${state.episode.malID}/metadata`)
+    .then((res) => res.json())
+    .then((data: Array<{ mal_id: number; title?: string }>) => {
+      data.forEach((item) => {
+        const card = episodeList.querySelector(`[data-episode-id="${item.mal_id}"]`);
+        if (!card) {
+          return;
+        }
+
+        if (item.title) {
+          const titleEl = card.querySelector("[data-episode-title]");
+          if (titleEl) {
+            titleEl.textContent = item.title;
+          }
+        }
+      });
+    })
+    .catch((error) => {
+      window.showToast?.({ message: "Failed to load episode metadata." });
+      console.error("failed to load episode metadata:", error);
+    });
+};