debug: add detailed error logging for Logto M2M token request failures

Logs the URL, resource, app ID prefix, and response body when the
token request fails — helps diagnose 400 errors from Logto.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/server/services/logto.service.ts

@@ -91,7 +91,17 @@ export class LogtoManagementClient {
 		});
 
 		if (!res.ok) {
-			throw new Error(`Logto M2M token request failed: HTTP ${res.status}`);
+			const errorBody = await res.text();
+			console.error(
+				`[Logto M2M] Token request failed: HTTP ${res.status}`,
+				`\n  URL: ${tokenUrl}`,
+				`\n  Resource: ${config.apiResource}`,
+				`\n  App ID: ${config.m2mAppId.slice(0, 8)}...`,
+				`\n  Response: ${errorBody}`,
+			);
+			throw new Error(
+				`Logto M2M token request failed: HTTP ${res.status} — ${errorBody}`,
+			);
 		}
 
 		const data = (await res.json()) as {