Remove app/Space folder and extract model business logic into services

Relocate all 14 files from the catch-all app/Space namespace into proper
locations: data providers to Support/Formatters, installation utilities to
Services/Installation, PDF utils to Services/Pdf, module/update classes to
Services/Module and Services/Update, SiteApi trait to Traits, and helpers
to Support.

Extract ~1,400 lines of business logic from 8 fat models (Invoice, Payment,
Estimate, RecurringInvoice, Company, Customer, Expense, User) into 9 new
service classes with constructor injection. Controllers now depend on
services instead of calling static model methods. Shared item/tax creation
logic consolidated into DocumentItemService.

app/Services/ExpenseService.php

@@ -0,0 +1,59 @@
+<?php
+
+namespace App\Services;
+
+use App\Models\CompanySetting;
+use App\Models\ExchangeRateLog;
+use App\Models\Expense;
+use Illuminate\Http\Request;
+
+class ExpenseService
+{
+    public function create(Request $request): Expense
+    {
+        $expense = Expense::create($request->getExpensePayload());
+
+        $companyCurrency = CompanySetting::getSetting('currency', $request->header('company'));
+
+        if ((string) $expense['currency_id'] !== $companyCurrency) {
+            ExchangeRateLog::addExchangeRateLog($expense);
+        }
+
+        if ($request->hasFile('attachment_receipt')) {
+            $expense->addMediaFromRequest('attachment_receipt')->toMediaCollection('receipts');
+        }
+
+        if ($request->customFields) {
+            $expense->addCustomFields(json_decode($request->customFields));
+        }
+
+        return $expense;
+    }
+
+    public function update(Expense $expense, Request $request): bool
+    {
+        $data = $request->getExpensePayload();
+
+        $expense->update($data);
+
+        $companyCurrency = CompanySetting::getSetting('currency', $request->header('company'));
+
+        if ((string) $data['currency_id'] !== $companyCurrency) {
+            ExchangeRateLog::addExchangeRateLog($expense);
+        }
+
+        if (isset($request->is_attachment_receipt_removed) && (bool) $request->is_attachment_receipt_removed) {
+            $expense->clearMediaCollection('receipts');
+        }
+        if ($request->hasFile('attachment_receipt')) {
+            $expense->clearMediaCollection('receipts');
+            $expense->addMediaFromRequest('attachment_receipt')->toMediaCollection('receipts');
+        }
+
+        if ($request->customFields) {
+            $expense->updateCustomFields(json_decode($request->customFields));
+        }
+
+        return true;
+    }
+}