Add user movie ratings and refresh movie cards

Store per-user 5-star ratings with averages and surface them in the player. Refresh movie list layout to show ratings and details in a cleaner card layout.

models/MovieRating.js

@@ -0,0 +1,11 @@
+const mongoose = require("mongoose");
+
+const movieRatingSchema = new mongoose.Schema({
+  movieId: { type: mongoose.Schema.Types.ObjectId, ref: "Movie", required: true, index: true },
+  userId: { type: mongoose.Schema.Types.ObjectId, ref: "User", required: true, index: true },
+  rating: { type: Number, required: true, min: 1, max: 5 },
+}, { timestamps: true });
+
+movieRatingSchema.index({ movieId: 1, userId: 1 }, { unique: true });
+
+module.exports = mongoose.model("MovieRating", movieRatingSchema);