feat: add logout endpoint and users/me endpoint

- POST /api/v1/logout: deletes client token, returns {status: ok}
- GET /api/v1/users/me: returns session info (delegates to HandleState)
- Add DeleteClient, GetSessionCount, ClientCountForSession, DeleteStaleSessions to db layer
- Add user count to GET /api/v1/server response
- Extract setupAPIv1 to fix funlen lint issue

internal/handlers/api.go

@@ -1361,20 +1361,71 @@ func (hdlr *Handlers) canAccessChannelHistory(
 	return true
 }
 
-// HandleServerInfo returns server metadata.
-func (hdlr *Handlers) HandleServerInfo() http.HandlerFunc {
-	type infoResponse struct {
-		Name string `json:"name"`
-		MOTD string `json:"motd"`
-	}
-
+// HandleLogout deletes the authenticated client's token.
+func (hdlr *Handlers) HandleLogout() http.HandlerFunc {
 	return func(
 		writer http.ResponseWriter,
 		request *http.Request,
 	) {
-		hdlr.respondJSON(writer, request, &infoResponse{
-			Name: hdlr.params.Config.ServerName,
-			MOTD: hdlr.params.Config.MOTD,
+		_, clientID, _, ok :=
+			hdlr.requireAuth(writer, request)
+		if !ok {
+			return
+		}
+
+		err := hdlr.params.Database.DeleteClient(
+			request.Context(), clientID,
+		)
+		if err != nil {
+			hdlr.log.Error(
+				"delete client failed", "error", err,
+			)
+			hdlr.respondError(
+				writer, request,
+				"internal error",
+				http.StatusInternalServerError,
+			)
+
+			return
+		}
+
+		hdlr.respondJSON(writer, request,
+			map[string]string{"status": "ok"},
+			http.StatusOK)
+	}
+}
+
+// HandleUsersMe returns the current user's session info.
+func (hdlr *Handlers) HandleUsersMe() http.HandlerFunc {
+	return hdlr.HandleState()
+}
+
+// HandleServerInfo returns server metadata.
+func (hdlr *Handlers) HandleServerInfo() http.HandlerFunc {
+	return func(
+		writer http.ResponseWriter,
+		request *http.Request,
+	) {
+		users, err := hdlr.params.Database.GetSessionCount(
+			request.Context(),
+		)
+		if err != nil {
+			hdlr.log.Error(
+				"get session count failed", "error", err,
+			)
+			hdlr.respondError(
+				writer, request,
+				"internal error",
+				http.StatusInternalServerError,
+			)
+
+			return
+		}
+
+		hdlr.respondJSON(writer, request, map[string]any{
+			"name":  hdlr.params.Config.ServerName,
+			"motd":  hdlr.params.Config.MOTD,
+			"users": users,
 		}, http.StatusOK)
 	}
 }