feat: implement freemium restrictions

go/internal/handler/billing.go

@@ -25,6 +25,46 @@ type PortalSessionResponse struct {
 	URL string `json:"url"`
 }
 
+// GetNetworkUsage returns the freemium quota state for the authenticated
+// caller's current network: how many messages they've used today, the daily
+// limit (null for pro), and when the counter resets.
+//
+// Authorization: any network member may read (not admin-only) since the UI
+// surfaces this to every sender.
+func (h *Handler) GetNetworkUsage(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
+	}
+
+	isMember, err := h.networkSvc.IsMember(r.Context(), networkID, humanId)
+	if err != nil {
+		slog.Error("failed to check network membership", "error", err, "network_id", networkID)
+		http.Error(w, "internal server error", http.StatusInternalServerError)
+		return
+	}
+	if !isMember {
+		http.Error(w, "forbidden", http.StatusForbidden)
+		return
+	}
+
+	usage, err := h.billingSvc.GetUsage(r.Context(), networkID)
+	if err != nil {
+		slog.Error("failed to get network usage", "error", err, "network_id", networkID)
+		http.Error(w, "internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	writeJSON(w, usage)
+}
+
 func (h *Handler) GetNetworkBilling(w http.ResponseWriter, r *http.Request) {
 	net, _, ok := h.loadNetworkForAdmin(w, r)
 	if !ok {