fix(security): enforce company scope on notes, doc-convert, and member bulk-delete (#668)

v3 port of the v2 authorization fixes.

- Notes IDOR (GHSA-85wc): NotePolicy checks the note's company_id and
  NotesController passes the bound model to authorize() on show/update/destroy.
- Estimate<->Invoice convert IDOR (GHSA-j2vg): EstimatesController::convertToInvoice
  and InvoicesController::convertToEstimate authorize 'view' on the source
  document before creating the target.
- Member bulk-delete (GHSA-wxrv): MembersController scopes ids via
  User::whereCompany() before MemberService::delete.

Adds feature tests for cross-company 403s + same-company happy paths.

tests/Feature/Admin/EstimateTest.php

@@ -5,6 +5,7 @@ use App\Http\Requests\DeleteEstimatesRequest;
 use App\Http\Requests\EstimatesRequest;
 use App\Http\Requests\SendEstimatesRequest;
 use App\Mail\SendEstimateMail;
+use App\Models\Company;
 use App\Models\Estimate;
 use App\Models\EstimateItem;
 use App\Models\Tax;
@@ -246,6 +247,16 @@ test('create invoice from estimate', function () {
     $response->assertStatus(200);
 });
 
+test('cannot convert an estimate belonging to another company', function () {
+    $estimate = Estimate::factory()->create([
+        'company_id' => Company::factory()->create()->id,
+        'estimate_date' => now(),
+        'expiry_date' => now()->addMonth(),
+    ]);
+
+    postJson("api/v1/estimates/{$estimate->id}/convert-to-invoice")->assertStatus(403);
+});
+
 test('delete multiple estimates using a form request', function () {
     $this->assertActionUsesFormRequest(
         EstimatesController::class,