fix(bots): intercept /confess so original never hits chat

Root cause of "not anonymous":
1. Confess deleted via raw SQL with no MESSAGE_DELETE broadcast
2. Frontend extractIds only accepted message_id, but deletes send id
   so live clients never removed deleted messages without refresh

Fix:
- Intercept /confess at message create: never store or broadcast the
  original; post only the anonymous bot message
- Accept both id and message_id on MESSAGE_DELETE in the WS store
- Include both fields on delete broadcasts

internal/message/handlers.go

@@ -27,6 +27,13 @@ type Handler struct {
 	pushHandler *push.Handler
 	logger      *slog.Logger
 	checker     *permissions.Checker
+	// Optional: intercepts /confess so the original message is never stored/broadcast.
+	confess ConfessHandler
+}
+
+// ConfessHandler posts an anonymous confession and returns the bot message payload.
+type ConfessHandler interface {
+	TryConfess(ctx context.Context, serverID, authorID, content string) (payload map[string]interface{}, handled bool)
 }
 
 func NewHandler(db *sql.DB, hub *gateway.Hub, pushHandler *push.Handler, logger *slog.Logger, checker *permissions.Checker) *Handler {
@@ -40,6 +47,11 @@ func NewHandler(db *sql.DB, hub *gateway.Hub, pushHandler *push.Handler, logger
 	}
 }
 
+// SetConfessHandler wires the built-in confess interceptor (optional).
+func (h *Handler) SetConfessHandler(c ConfessHandler) {
+	h.confess = c
+}
+
 func (h *Handler) RegisterRoutes(r chi.Router) {
 	r.Get("/", h.List)
 	r.Post("/", h.Create)
@@ -119,6 +131,7 @@ func (h *Handler) BulkDelete(w http.ResponseWriter, r *http.Request) {
 				Type: gateway.EventMessageDelete,
 				Data: map[string]string{
 					"id":         id,
+					"message_id": id,
 					"channel_id": channelID,
 				},
 			})
@@ -243,6 +256,16 @@ func (h *Handler) Create(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Anonymous confessions: never store/broadcast the original /confess message.
+	if h.confess != nil {
+		if payload, handled := h.confess.TryConfess(r.Context(), serverID, userID, req.Content); handled {
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusCreated)
+			json.NewEncoder(w).Encode(payload)
+			return
+		}
+	}
+
 	var msg messageResponse
 	var editedAt sql.NullString
 	var createdAt sql.NullString
@@ -467,6 +490,7 @@ func (h *Handler) Delete(w http.ResponseWriter, r *http.Request) {
 			Type: gateway.EventMessageDelete,
 			Data: map[string]string{
 				"id":         messageID,
+				"message_id": messageID,
 				"channel_id": channelID,
 			},
 		})