Add migration to backfill terms of use

database/migrations/2026_07_13_075347_backfill_policy_acceptance_existing_users.php

@@ -0,0 +1,61 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+return new class() extends Migration {
+    /**
+     * Users created before this timestamp are treated as having accepted
+     * our existing terms of use. Users created afterwards go through our
+     * new policy flow (T430529) and are excluded from the backfill.
+     */
+    private const USER_CREATED_AT_CUTOFF = '2026-07-13 08:00:00';
+
+    /**
+     * Run the migrations.
+     */
+    public function up(): void {
+        $policyId = $this->getPolicyId();
+        $timestamp = now();
+
+        DB::table('users')
+            ->leftJoin('policy_acceptances', fn ($join) => $join->on('users.id', '=', 'user_id')
+                ->where('policy_id', '=', $policyId)
+            )
+            ->whereNull('policy_id')
+            ->where('users.created_at', '<', self::USER_CREATED_AT_CUTOFF)
+            ->orderBy('users.id')
+            ->select('users.id', 'users.created_at')
+            ->chunkById(100, fn ($users) => DB::table('policy_acceptances')->insert(
+                $users->map(fn ($user) => [
+                    'user_id' => $user->id,
+                    'policy_id' => $policyId,
+                    'accepted_at' => $user->created_at,
+                    'created_at' => $timestamp,
+                    'updated_at' => $timestamp,
+                ])->all()
+            ),
+                'users.id', 'id');
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void {
+        DB::table('policy_acceptances')
+            ->where('policy_id', $this->getPolicyId())
+            ->where('accepted_at', '<', self::USER_CREATED_AT_CUTOFF)
+            ->whereColumn('created_at', '>', 'accepted_at')
+            ->delete();
+    }
+
+    /**
+     * @return int The policy ID of our existing terms of use.
+     */
+    private function getPolicyId(): int {
+        return DB::table('policies')
+            ->where('policy_type', 'terms-of-use')
+            ->where('active_from', '2022-01-01')
+            ->soleValue('id');
+    }
+};