Add multi-branch POS with team roles and branch-scoped cashiers.

Pro and Business users can manage branches, invite cashiers with branch assignment, and switch registers; sales and register flows respect acting location.

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

app/Http/Controllers/AccountSwitchController.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+
+class AccountSwitchController extends Controller
+{
+    public function switch(Request $request): RedirectResponse
+    {
+        $data = $request->validate([
+            'account' => ['required', 'integer'],
+        ]);
+
+        abort_unless($request->user()->canAccessAccount($data['account']), 403);
+
+        $request->session()->put('ladill_account', $data['account']);
+        $request->session()->forget('ladill_pos_location');
+
+        return back();
+    }
+}