feat(provider): add health-probe contract and supporting value objects

Add getName(), ping(), and probe() to ProviderInterface. Introduce
ProbeTrait to classify HTTP/transport exceptions into typed error codes,
ProviderStatus as the result value object, and ProviderStatusType /
ProviderErrorCode as backing enums.

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

src/Service/ProbeTrait.php

@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use Symfony\Contracts\HttpClient\Exception\HttpExceptionInterface;
+use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
+
+trait ProbeTrait
+{
+    public function probe(): ProviderStatus
+    {
+        if (!$this->isConfigured()) {
+            return new ProviderStatus($this->getName(), ProviderStatusType::NotConfigured);
+        }
+
+        try {
+            $this->ping();
+
+            return new ProviderStatus($this->getName(), ProviderStatusType::Ok);
+        } catch (\Throwable $e) {
+            return $this->statusFromException($e);
+        }
+    }
+
+    private function statusFromException(\Throwable $e): ProviderStatus
+    {
+        [$error, $message] = $this->classifyException($e);
+
+        return new ProviderStatus($this->getName(), ProviderStatusType::Error, $error, $message);
+    }
+
+    /** @return array{ProviderErrorCode, string} */
+    private function classifyException(\Throwable $e): array
+    {
+        if ($e instanceof TransportExceptionInterface) {
+            return [ProviderErrorCode::UrlUnreachable, 'Could not reach the server: ' . $e->getMessage()];
+        }
+
+        if ($e instanceof HttpExceptionInterface) {
+            $code = $e->getResponse()->getStatusCode();
+
+            return match (true) {
+                $code === 401 => [ProviderErrorCode::AuthFailed, 'Invalid or expired token — verify your credentials'],
+                $code === 403 => [ProviderErrorCode::AuthFailed, 'Access denied — token lacks the required scopes'],
+                $code === 404 => [ProviderErrorCode::UrlUnreachable, 'Endpoint not found — check the configured URL'],
+                default       => [ProviderErrorCode::Unknown, "HTTP {$code}: " . $e->getMessage()],
+            };
+        }
+
+        $msg   = $e->getMessage();
+        $lower = strtolower($msg);
+        $error = match (true) {
+            str_contains($msg, 'not found') || str_contains($msg, 'Could not resolve') => ProviderErrorCode::UserNotFound,
+            str_contains($msg, 'GraphQL error')
+                && (str_contains($lower, 'unauthorized') || str_contains($lower, 'bad credentials')) => ProviderErrorCode::AuthFailed,
+            default => ProviderErrorCode::Unknown,
+        };
+
+        return [$error, $msg];
+    }
+}

src/Service/ProviderErrorCode.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+enum ProviderErrorCode: string
+{
+    case AuthFailed     = 'auth_failed';
+    case UrlUnreachable = 'url_unreachable';
+    case UserNotFound   = 'user_not_found';
+    case Unknown        = 'unknown';
+}

src/Service/ProviderInterface.php

@@ -10,4 +10,10 @@ interface ProviderInterface
     public function fetch(): array;
 
     public function isConfigured(): bool;
+
+    public function getName(): string;
+
+    public function probe(): ProviderStatus;
+
+    public function ping(): void;
 }

src/Service/ProviderStatus.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+final class ProviderStatus
+{
+    public function __construct(
+        public readonly string $name,
+        public readonly ProviderStatusType $status,
+        public readonly ?ProviderErrorCode $error = null,
+        public readonly ?string $message = null,
+    ) {}
+
+    /** @return array<string, string> */
+    public function toArray(): array
+    {
+        $data = ['status' => $this->status->value];
+        if ($this->error !== null) {
+            $data['error'] = $this->error->value;
+        }
+        if ($this->message !== null) {
+            $data['message'] = $this->message;
+        }
+
+        return $data;
+    }
+}

src/Service/ProviderStatusType.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+enum ProviderStatusType: string
+{
+    case Ok            = 'ok';
+    case Error         = 'error';
+    case NotConfigured = 'not_configured';
+}