Add video engagement tracking and heatmap

database/migrations/2026_07_19_141500_create_video_engagement_table.php

@@ -0,0 +1,33 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('video_engagement', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('episode_id')->constrained('episodes')->cascadeOnDelete();
+            $table->foreignId('user_id')->constrained('users')->cascadeOnDelete();
+            $table->unsignedSmallInteger('segment');
+            $table->timestamps();
+
+            // One row per user per episode per segment — no duplicates
+            $table->unique(['episode_id', 'user_id', 'segment']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('video_engagement');
+    }
+};