fix: resolve PHPStan level 9 errors

- Simplify json payload parsing (remove redundant is_object/method_exists)
- Add @var string annotation for field_type in WebhookService
- Ensure payload is typed as array<string, mixed> before passing to services
- Remove stale baseline patterns (route prefix, cast mixed)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: tanhongit

phpstan-baseline.neon

@@ -1,20 +1,5 @@
 parameters:
     ignoreErrors:
-        - message: '#Parameter \#1 \$prefix of static method Illuminate\\Support\\Facades\\Route::prefix\(\) expects string, mixed given\.#'
-          path: routes/*.php
-
-        - message: '#Part \$routePrefix \(mixed\) of encapsed string cannot be cast to string\.#'
-          path: routes/*.php
-
-        - message: '#Cannot cast mixed to string#'
-          path: src/*.php
-
-        - message: '#Cannot cast mixed to int#'
-          path: src/*.php
-
-        - message: '#Cannot access offset .+ on mixed#'
-          path: src/*.php
-
         - message: '#Parameter \#1 \$view of function view expects view-string\|null, string given\.#'
           paths:
               - src/Services/GithubService.php

src/Actions/GenerateCommentAction.php

@@ -29,22 +29,17 @@ public function __invoke(Request $request, bool $validate = true): JsonResponse
 
         try {
             if ($request->isJson()) {
-                $jsonContent = $request->json();
-                $payload = is_object($jsonContent) && method_exists($jsonContent, 'all')
-                    ? $jsonContent->all()
-                    : (array) $jsonContent;
+                /** @var array<string, mixed> $payload */
+                $payload = $request->json()->all();
             } else {
-                $payload = json_decode($request->getContent(), true);
+                /** @var array<string, mixed> $payload */
+                $payload = (array) json_decode($request->getContent(), true);
             }
 
-            if (!empty($payload['payload'])) {
+            if (isset($payload['payload']) && is_array($payload['payload'])) {
                 $payload = $payload['payload'];
             }
 
-            if (is_string($payload)) {
-                $payload = json_decode($payload, true);
-            }
-
             if ($validate) {
                 $validationResponse = $this->webhookService->validatePayloadForComment($payload);
                 if ($validationResponse !== null) {

src/Services/WebhookService.php

@@ -42,6 +42,7 @@ protected function hasValidNodeAndFieldData(array $payload): bool
      */
     protected function hasFieldTemplate(array $payload): bool
     {
+        /** @var string $fieldType */
         $fieldType = $payload['changes']['field_value']['field_type'] ?? '';
 
         return view()->exists('github-project::md.field_types.'.$fieldType);