feat: send email notifications for missed messages

- New cron job in cluster
- Handle presence and other concerns
- Toggle in app to disable email notifications
- Handles other edge cases such as cooldown period
- Simple html email with simple message

Closes #117

go/internal/handler/handler.go

@@ -50,10 +50,11 @@ func NewHandler(authSvc auth.AuthService, humanSvc human.Service, networkSvc net
 // Response DTOs
 
 type Human struct {
-	Id          string    `json:"id"`
-	Email       string    `json:"email"`
-	EmailPrefix string    `json:"email_prefix"`
-	CreatedAt   time.Time `json:"created_at"`
+	Id                        string    `json:"id"`
+	Email                     string    `json:"email"`
+	EmailPrefix               string    `json:"email_prefix"`
+	EmailNotificationsEnabled bool      `json:"email_notifications_enabled"`
+	CreatedAt                 time.Time `json:"created_at"`
 }
 
 type Network struct {
@@ -267,6 +268,35 @@ func (h *Handler) GetCurrentHuman(w http.ResponseWriter, r *http.Request) {
 	json.NewEncoder(w).Encode(dto)
 }
 
+type UpdateSettingsRequest struct {
+	EmailNotificationsEnabled *bool `json:"email_notifications_enabled"`
+}
+
+// UpdateSettings updates the authenticated human's settings
+func (h *Handler) UpdateSettings(w http.ResponseWriter, r *http.Request) {
+	humanId, ok := middleware.HumanIdFromContext(r.Context())
+	if !ok {
+		http.Error(w, "unauthorized", http.StatusUnauthorized)
+		return
+	}
+
+	var req UpdateSettingsRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "invalid request body", http.StatusBadRequest)
+		return
+	}
+
+	if req.EmailNotificationsEnabled != nil {
+		if err := h.humanSvc.UpdateEmailNotificationsEnabled(r.Context(), humanId, *req.EmailNotificationsEnabled); err != nil {
+			slog.Error("failed to update email notifications setting", "error", err, "humanId", humanId)
+			http.Error(w, "internal server error", http.StatusInternalServerError)
+			return
+		}
+	}
+
+	w.WriteHeader(http.StatusNoContent)
+}
+
 // ============================================================================
 // Network Handlers
 // ============================================================================
@@ -953,10 +983,11 @@ func waitlistEntryToDTO(e *waitlist.WaitlistEntry) WaitlistEntryResponse {
 
 func humanToDTO(h *human.Human) Human {
 	return Human{
-		Id:          h.ID,
-		Email:       h.Email,
-		EmailPrefix: h.EmailPrefix,
-		CreatedAt:   h.CreatedAt,
+		Id:                        h.ID,
+		Email:                     h.Email,
+		EmailPrefix:               h.EmailPrefix,
+		EmailNotificationsEnabled: h.EmailNotificationsEnabled,
+		CreatedAt:                 h.CreatedAt,
 	}
 }