fix: address authentication system issues

- Fix GraphQL authorization attributes to use string[] instead of string for roles
- Remove admin role requirement from ImportNovel endpoint
- Add comprehensive OIDC configuration validation with specific error messages
- Validate Authority, ClientId, and Audience are properly configured
- Ensure HTTPS requirement except for localhost development

Co-authored-by: conco <conco@users.noreply.local>

FictionArchive.Service.NovelService/GraphQL/Mutation.cs

@@ -13,7 +13,7 @@ namespace FictionArchive.Service.NovelService.GraphQL;
 
 public class Mutation
 {
-    [Authorize(Roles = "admin")]
+    [Authorize]
     public async Task<NovelUpdateRequestedEvent> ImportNovel(string novelUrl, NovelUpdateService service)
     {
         return await service.QueueNovelImport(novelUrl);