feat: [document] 문서양식/문서 이미지를 R2 presigned URL로 전환

- 업로드 응답에 image_url 추가
- prepareTemplateData에서 file_id/image_path 기반 presigned URL 발급
- edit/preview에서 image_url 우선 사용
- show/print에서 api.sam.kr 하드코딩 제거

app/Http/Controllers/DocumentTemplateController.php

@@ -130,6 +130,47 @@ public function blockEdit(int $id): View
     /**
      * 현재 선택된 테넌트 조회
      */
+    /**
+     * API에서 presigned URL 발급
+     */
+    private function getPresignedUrlFromApi(int $fileId): ?string
+    {
+        $baseUrl = config('services.api.base_url', 'https://api.sam.kr');
+        $apiKey = config('services.api.key');
+        $token = session('api_access_token', '');
+
+        $response = \Illuminate\Support\Facades\Http::baseUrl($baseUrl)
+            ->withoutVerifying()
+            ->withHeaders([
+                'X-API-KEY' => $apiKey,
+                'X-TENANT-ID' => session('selected_tenant_id', 1),
+            ])
+            ->withToken($token)
+            ->timeout(10)
+            ->get("/api/v1/files/{$fileId}/presigned-url");
+
+        return $response->successful() ? $response->json('data.url') : null;
+    }
+
+    private function getPresignedUrlByPath(string $path): ?string
+    {
+        $baseUrl = config('services.api.base_url', 'https://api.sam.kr');
+        $apiKey = config('services.api.key');
+        $token = session('api_access_token', '');
+
+        $response = \Illuminate\Support\Facades\Http::baseUrl($baseUrl)
+            ->withoutVerifying()
+            ->withHeaders([
+                'X-API-KEY' => $apiKey,
+                'X-TENANT-ID' => session('selected_tenant_id', 1),
+            ])
+            ->withToken($token)
+            ->timeout(10)
+            ->post('/api/v1/files/presigned-url-by-path', ['path' => $path]);
+
+        return $response->successful() ? $response->json('data.url') : null;
+    }
+
     private function getCurrentTenant(): ?Tenant
     {
         $tenantId = session('selected_tenant_id');
@@ -244,10 +285,19 @@ private function prepareTemplateData(DocumentTemplate $template): array
                 ];
             })->toArray(),
             'sections' => $template->sections->map(function ($s) {
+                $imageUrl = null;
+                if ($s->file_id) {
+                    $imageUrl = $this->getPresignedUrlFromApi($s->file_id);
+                } elseif ($s->image_path) {
+                    $imageUrl = $this->getPresignedUrlByPath($s->image_path);
+                }
+
                 return [
                     'id' => $s->id,
                     'title' => $s->title,
                     'image_path' => $s->image_path,
+                    'file_id' => $s->file_id,
+                    'image_url' => $imageUrl,
                     'items' => $s->items->map(function ($i) {
                         $fv = $i->field_values ?? [];