feat: add Amvstrm as source for /episodes

Summary:

Test Plan:

src/controllers/episodes/index.ts

@@ -57,6 +57,10 @@ app.openapi(route, async (c) => {
       import("./consumet").then(({ getEpisodesFromConsumet }) =>
         getEpisodesFromConsumet(aniListId),
       ),
+    () =>
+      import("./amvstrm").then(({ getEpisodesFromAmvstrm }) =>
+        getEpisodesFromAmvstrm(aniListId),
+      ),
   ]);
 
   if (!episodes) {