Improve exception handling and default behaviors in Unit class

Enhanced `Unit` class by refining exception handling for `loadCertificates`, `loadJsModules`, and `getCertificate` methods. Introduced default empty arrays and specific exceptions for better runtime resilience. Updated `UnitException` instantiation with error codes for richer context. Adjusted README badges for added links and improved visibility.

Author: Pavlusha311245

README.md

@@ -8,11 +8,11 @@
 
 <p align="center">
 <a href="https://packagist.org/packages/pavlusha311245/unit-php-sdk"><img src="https://img.shields.io/packagist/v/Pavlusha311245/unit-php-sdk?labelColor=%231e293b&color=%23702963&link=https%3A%2F%2Fpackagist.org%2Fpackages%2Fpavlusha311245%2Funit-php-sdk" alt="packagist link"></a>
-<a href="https://unit-sdk.pavlusha.me/"><img src="https://img.shields.io/website?url=https%3A%2F%2Funit-sdk.pavlusha.me%2F&label=documentation&link=https%3A%2F%2Funit-sdk.pavlusha.me%2F" alt="documentation link"></a>
 <img src="https://github.com/Pavlusha311245/nginx-unit-php-sdk/actions/workflows/deploy_codecov.yaml/badge.svg" alt="documentation link">
 <a href="https://codecov.io/gh/Pavlusha311245/nginx-unit-php-sdk" > 
  <img src="https://codecov.io/gh/Pavlusha311245/nginx-unit-php-sdk/graph/badge.svg?token=FGTTDSJ7BX" alt="Codecov dabge"/> 
  </a>
+<a href="https://deepwiki.com/Pavlusha311245/nginx-unit-php-sdk"><img src="https://deepwiki.com/badge.svg" alt="Ask DeepWiki"></a>
 </p>
 
 ## About

src/Http/UnitRequest.php

@@ -93,7 +93,7 @@ public function send($uri, bool $associative = true, array $requestOptions = [])
 //            $responseBody = $e->hasResponse() ? $e->getResponse()->getBody()->getContents() : null;
 //            throw new UnitException($responseBody ? json_decode($responseBody)['error'] : '');
 
-            throw new UnitException($e->getMessage());
+            throw new UnitException($e->getMessage(), $e->getCode());
         }
 
         $rawData = json_decode($response->getBody()->getContents(), $associative);

src/Unit.php

@@ -108,9 +108,17 @@ private function loadConfig(): void
      */
     public function getCertificates(): array
     {
-        $this->loadCertificates();
+        try {
+            $this->loadCertificates();
+
+            return $this->certificates;
+        } catch (UnitException $exception) {
+            if ($exception->getCode() == 404) {
+                return [];
+            }
 
-        return $this->certificates;
+            throw new UnitException($exception->getMessage());
+        }
     }
 
     /**
@@ -221,10 +229,14 @@ public function setJsModules(array $js_modules): void
      */
     private function loadJsModules(): void
     {
-        $result = $this->request->send(ApiPathEnum::JS_MODULES->value);
+        try {
+            $result = $this->request->send(ApiPathEnum::JS_MODULES->value);
 
-        foreach ($result as $key => $value) {
-            $this->js_modules[$key] = new JsModule($key, $value);
+            foreach ($result as $key => $value) {
+                $this->js_modules[$key] = new JsModule($key, $value);
+            }
+        } catch (UnitException $exception) {
+            $this->js_modules = [];
         }
     }
 
@@ -243,9 +255,17 @@ private function loadStatistics(): void
      */
     public function getCertificate(string $certificateName): ?CertificateInterface
     {
-        $this->loadCertificates();
+        try {
+            $this->loadCertificates();
 
-        return $this->certificates[$certificateName] ?? null;
+            return $this->certificates[$certificateName];
+        } catch (UnitException $exception) {
+            if ($exception->getCode() == 404) {
+                throw new UnitException('Certificate not found');
+            }
+
+            throw new UnitException($exception->getMessage());
+        }
     }
 
     /**