refactor(services): Documents→Document + ExchangeRate→Integrations/ExchangeRate

Two follow-ups to the Services reorg that landed in 6d1816bd.

**Documents → Document** (singular). Documents/ was the only plural subdir in app/Services/ — every other bucket (Company, Mail, Module, Pdf, Storage, Update, ExchangeRate) was singular. Renaming to Document/ normalizes the whole tree.

**ExchangeRate → Integrations/ExchangeRate**. Introduces Integrations/ as an umbrella for external-service adapter subsystems. Exchange rate providers move in first; AI providers, payment gateways, and any other driver-pattern integrations land as sibling subdirs (Integrations/Ai/, Integrations/Payment/) without another reorg. Integrations/ was chosen over Providers/ to avoid conceptual collision with Laravel's app/Providers/ — 'check the providers' shouldn't be ambiguous.

17 files moved, 21 consumer files rewritten to point at the new namespaces via literal-string replacement (same approach as the previous reorg). 350 tests pass, Pint clean.

app/Services/Document/TransactionService.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Services\Document;
+
+use App\Facades\Hashids;
+use App\Models\Transaction;
+
+class TransactionService
+{
+    public function create(array $data): Transaction
+    {
+        $transaction = Transaction::create($data);
+        $transaction->unique_hash = Hashids::connection(Transaction::class)->encode($transaction->id);
+        $transaction->save();
+
+        return $transaction;
+    }
+
+    public function complete(Transaction $transaction): void
+    {
+        $transaction->status = Transaction::SUCCESS;
+        $transaction->save();
+    }
+
+    public function fail(Transaction $transaction): void
+    {
+        $transaction->status = Transaction::FAILED;
+        $transaction->save();
+    }
+}