Fix cashier desk: unpaid bills on every demo branch.

Demo seeding used i%3 for both branch and paid status, so Ridge Clinic only got paid invoices. Cashiers now default to outstanding balances and Call next is secondary to the walk-up unpaid list.

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

tests/Feature/DemoSeedCommandTest.php

@@ -377,6 +377,28 @@ class DemoSeedCommandTest extends TestCase
             $this->assertNotNull($waiter->practitioner_id, 'Demo waiters must all have a doctor assigned');
             $this->assertNotSame('unresolved', $waiter->queue_routing_status);
         }
+
+        $branches = Branch::query()->where('organization_id', $org->id)->orderBy('id')->get();
+        $this->assertGreaterThanOrEqual(3, $branches->count());
+        foreach ($branches as $branch) {
+            $unpaid = Bill::query()
+                ->where('organization_id', $org->id)
+                ->where('branch_id', $branch->id)
+                ->where('balance_minor', '>', 0)
+                ->count();
+            $this->assertGreaterThan(
+                0,
+                $unpaid,
+                "Branch {$branch->name} must have unpaid demo invoices for cashiers",
+            );
+        }
+
+        $cashier = \App\Models\Member::query()
+            ->where('organization_id', $org->id)
+            ->where('role', 'cashier')
+            ->first();
+        $this->assertNotNull($cashier);
+        $this->assertSame((int) $branches->first()->id, (int) $cashier->branch_id);
     }
 
     public function test_specialty_doctor_links_after_sso_public_id_remap(): void