feat: allow network admin to control ephemerality setting

Resolves #92

go/internal/handler/handler.go

@@ -48,11 +48,12 @@ type Human struct {
 }
 
 type Network struct {
-	Id         string    `json:"id"`
-	Name       string    `json:"name"`
-	AdminHuman Human     `json:"admin_human"`
-	Humans     []Human   `json:"humans"`
-	CreatedAt  time.Time `json:"created_at"`
+	Id                    string    `json:"id"`
+	Name                  string    `json:"name"`
+	AdminHuman            Human     `json:"admin_human"`
+	Humans                []Human   `json:"humans"`
+	MessageRetentionHours int       `json:"message_retention_hours"`
+	CreatedAt             time.Time `json:"created_at"`
 }
 
 // Auth Request/Response DTOs
@@ -85,6 +86,10 @@ type SetOpenStreamCapacityRequest struct {
 	Capacity int `json:"capacity"`
 }
 
+type SetMessageRetentionHoursRequest struct {
+	Hours int `json:"hours"`
+}
+
 type MembersRequest struct {
 	Emails []string `json:"emails"`
 }
@@ -649,6 +654,72 @@ func (h *Handler) RevokeInvitation(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusNoContent)
 }
 
+// SetMessageRetentionHours updates the message retention window for a network (admin-only)
+func (h *Handler) SetMessageRetentionHours(w http.ResponseWriter, r *http.Request) {
+	humanId, ok := middleware.HumanIdFromContext(r.Context())
+	if !ok {
+		http.Error(w, "unauthorized", http.StatusUnauthorized)
+		return
+	}
+
+	networkID := r.PathValue("id")
+	if networkID == "" {
+		http.Error(w, "network id is required", http.StatusBadRequest)
+		return
+	}
+
+	// Fetch network to verify admin
+	net, err := h.networkSvc.GetByID(r.Context(), networkID)
+	if err != nil {
+		if errors.Is(err, network.ErrNotFound) {
+			http.Error(w, "network not found", http.StatusNotFound)
+			return
+		}
+		slog.Error("failed to get network", "error", err, "network_id", networkID)
+		http.Error(w, "internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	if net.AdminHumanId != humanId {
+		http.Error(w, "only the network admin can change this setting", http.StatusForbidden)
+		return
+	}
+
+	var req SetMessageRetentionHoursRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "invalid request body", http.StatusBadRequest)
+		return
+	}
+
+	if err := h.networkSvc.SetMessageRetentionHours(r.Context(), networkID, req.Hours); err != nil {
+		if errors.Is(err, network.ErrInvalidRetentionHours) {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		slog.Error("failed to set message retention hours", "error", err, "network_id", networkID)
+		http.Error(w, "internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	// Return updated network
+	updatedNet, err := h.networkSvc.GetByID(r.Context(), networkID)
+	if err != nil {
+		slog.Error("failed to get network after update", "error", err, "network_id", networkID)
+		http.Error(w, "internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	resp, err := h.networkToDTO(r.Context(), updatedNet)
+	if err != nil {
+		slog.Error("failed to convert network to DTO", "error", err, "network_id", networkID)
+		http.Error(w, "internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(resp)
+}
+
 // DownloadParticleMedia returns a fresh signed download URL for media/file particles
 func (h *Handler) DownloadParticleMedia(w http.ResponseWriter, r *http.Request) {
 	_, ok := middleware.EmailFromContext(r.Context())
@@ -960,11 +1031,12 @@ func (h *Handler) networkToDTO(ctx context.Context, n *network.Network) (Network
 	}
 
 	return Network{
-		Id:         n.ID,
-		Name:       n.Name,
-		AdminHuman: humanToDTO(adminHuman),
-		Humans:     humans,
-		CreatedAt:  n.CreatedAt,
+		Id:                    n.ID,
+		Name:                  n.Name,
+		AdminHuman:            humanToDTO(adminHuman),
+		Humans:                humans,
+		MessageRetentionHours: n.MessageRetentionHours,
+		CreatedAt:             n.CreatedAt,
 	}, nil
 }