Initial commit: standalone quiz-testing system

Full-stack F# (Domain/Server/Client via Fable+Elmish+Feliz), PostgreSQL
persistence via Dapper, Docker Compose deployment. Student quiz-taking flow
with time-limit enforcement and focus-loss tracking, Teacher question bank
and quiz builder with results analytics, Admin user management.

src/Server/Features/Teacher/CreateTopic.fs

@@ -0,0 +1,24 @@
+module Server.Features.Teacher.CreateTopic
+
+open Giraffe
+open Domain
+open Domain.Contracts
+open Server.Store
+
+let private create (store: Store) (ownerId: UserId) (req: CreateTopicRequest) : Result<Topic, string> =
+    if System.String.IsNullOrWhiteSpace req.Name then
+        Error "Название темы не может быть пустым"
+    else
+        let topic: Topic = { Id = Id.newTopicId (); OwnerId = ownerId; Name = req.Name }
+        store.AddTopic topic
+        Ok topic
+
+let handler (store: Store) : HttpHandler =
+    bindJson<CreateTopicRequest> (fun req next ctx ->
+        task {
+            let result =
+                Server.Auth.requireRole [ Teacher; Admin ] ctx.User
+                |> Result.bind (fun uid -> create store uid req)
+
+            return! json result next ctx
+        })