feat:E-Sign 계약 생성 영업파트너 검색 모달 추가

- EsignApiController에 searchPartners() 검색 API 추가
- SalesPartner 모델 $fillable에 company_name, biz_no, address 추가
- User 모델에 salesPartner() HasOne 관계 추가
- create.blade.php에 PartnerSearchModal 컴포넌트 + 자동채우기 로직 추가
- web.php에 search-partners 라우트 추가

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Http/Controllers/ESign/EsignApiController.php

@@ -5,6 +5,7 @@
 use App\Http\Controllers\Controller;
 use App\Mail\EsignRequestMail;
 use App\Models\ESign\EsignContract;
+use App\Models\User;
 use App\Services\ESign\DocxToPdfConverter;
 use App\Models\ESign\EsignFieldTemplate;
 use App\Models\ESign\EsignFieldTemplateItem;
@@ -22,6 +23,43 @@
 
 class EsignApiController extends Controller
 {
+    /**
+     * 영업파트너 검색
+     */
+    public function searchPartners(Request $request): JsonResponse
+    {
+        $q = trim($request->input('q', ''));
+
+        $query = User::where('is_active', true)
+            ->whereIn('role', ['sales', 'manager'])
+            ->with('salesPartner');
+
+        if ($q !== '') {
+            $query->where(function ($w) use ($q) {
+                $w->where('name', 'like', "%{$q}%")
+                  ->orWhere('email', 'like', "%{$q}%")
+                  ->orWhere('phone', 'like', "%{$q}%");
+            });
+        }
+
+        $users = $query->orderBy('name')->limit(20)->get();
+
+        $data = $users->map(function ($user) {
+            $sp = $user->salesPartner;
+            return [
+                'id' => $user->id,
+                'name' => $user->name,
+                'phone' => $user->phone,
+                'email' => $user->email,
+                'company_name' => $sp?->company_name,
+                'biz_no' => $sp?->biz_no,
+                'address' => $sp?->address,
+            ];
+        });
+
+        return response()->json(['success' => true, 'data' => $data]);
+    }
+
     /**
      * 법인도장 조회
      */