feat: add Amvstrm as provider for stream URL

Summary:

Test Plan:

src/controllers/episodes/getEpisodeUrl/index.ts

@@ -112,6 +112,26 @@ app.openapi(route, async (c) => {
     }
   }
 
+  if (provider === "amvstrm") {
+    try {
+      const result = await import("./amvstrm").then(
+        ({ getSourcesFromAmvstrm }) => getSourcesFromAmvstrm(id),
+      );
+      if (!result) {
+        return c.json({ success: false }, { status: 404 });
+      }
+
+      return c.json({
+        success: true,
+        result,
+      });
+    } catch (e) {
+      console.error("Failed to fetch download URL from Amvstrm", e);
+
+      return c.json(ErrorResponse, { status: 500 });
+    }
+  }
+
   return c.json(ErrorResponse, { status: 400 });
 });