fix: [daily-work-log] 파일 저장 정책 준수 (docs 기준)

- 경로: {tenant_id}/daily-work-log/{year}/{month}/{hex}.ext 형식으로 변경
- 파일명: UUID → 64bit 난수 hex (bin2hex(random_bytes(8)))
- 최대 크기: 10MB → 20MB (file-storage-guide.md 기준)

app/Http/Controllers/Finance/DailyWorkLogController.php

@@ -9,7 +9,6 @@
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Storage;
-use Illuminate\Support\Str;
 
 class DailyWorkLogController extends Controller
 {
@@ -201,7 +200,7 @@ public function uploadFile(Request $request): JsonResponse
         $request->validate([
             'log_date' => 'required|date',
             'field_key' => 'required|in:memo,reflection',
-            'file' => 'required|file|max:10240',
+            'file' => 'required|file|max:20480',
         ]);
 
         $tenantId = session('selected_tenant_id', 1);
@@ -212,9 +211,10 @@ public function uploadFile(Request $request): JsonResponse
         );
 
         $file = $request->file('file');
-        $storedName = Str::uuid().'.'.$file->getClientOriginalExtension();
-        $basePath = "daily-work-log/{$tenantId}/{$log->id}";
-        $filePath = "{$basePath}/{$storedName}";
+        $storedName = bin2hex(random_bytes(8)).'.'.$file->getClientOriginalExtension();
+        $year = date('Y');
+        $month = date('m');
+        $filePath = "{$tenantId}/daily-work-log/{$year}/{$month}/{$storedName}";
 
         Storage::disk('tenant')->put($filePath, file_get_contents($file));