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.SchedulerService/GraphQL/Mutation.cs

@@ -11,21 +11,21 @@ public class Mutation
 {
     [Error<DuplicateNameException>]
     [Error<FormatException>]
-    [Authorize(Roles = "admin")]
+    [Authorize(Roles = new[] { "admin" })]
     public async Task<SchedulerJob> ScheduleEventJob(string key, string description, string eventType, string eventData, string cronSchedule, JobManagerService jobManager)
     {
         return await jobManager.ScheduleEventJob(key, description, eventType, eventData, cronSchedule);
     }
 
     [Error<JobPersistenceException>]
-    [Authorize(Roles = "admin")]
+    [Authorize(Roles = new[] { "admin" })]
     public async Task<bool> RunJob(string jobKey, JobManagerService jobManager)
     {
         return await jobManager.TriggerJob(jobKey);
     }
 
     [Error<KeyNotFoundException>]
-    [Authorize(Roles = "admin")]
+    [Authorize(Roles = new[] { "admin" })]
     public async Task<bool> DeleteJob(string jobKey, JobManagerService jobManager)
     {
         bool deleted = await jobManager.DeleteJob(jobKey);