Backfill existing rooms to public so older shared links are joinable.

Co-authored-by: Cursor <cursoragent@cursor.com>

database/migrations/2026_07_11_160000_clear_invite_only_on_existing_rooms.php

@@ -0,0 +1,28 @@
+<?php
+
+use App\Models\Room;
+use Illuminate\Database\Migrations\Migration;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Room::withTrashed()
+            ->whereNotNull('settings')
+            ->get()
+            ->each(function (Room $room): void {
+                $settings = $room->settings;
+                if (! is_array($settings) || empty($settings['invite_only'])) {
+                    return;
+                }
+
+                $settings['invite_only'] = false;
+                $room->forceFill(['settings' => $settings])->saveQuietly();
+            });
+    }
+
+    public function down(): void
+    {
+        // Prior invite-only state is not restored.
+    }
+};