feat: Kunden-Seite zeigt API-Keys beim Aufklappen

- Klick auf Kundenzeile klappt Key-Panel auf
- Zeigt Agent + Read-only Keys mit Permission-Badge
- Key teilweise maskiert, Kopier-Button vorhanden
- Backend: GET /api/v1/customers/{id}/apikeys
- DB: ListCustomerAPIKeys() nach customer_id gefiltert

backend/api/apikeys.go

@@ -58,6 +58,21 @@ func (h *Handler) createAPIKey(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusCreated, apiKey)
 }
 
+// GET /api/v1/customers/{id}/apikeys
+func (h *Handler) listCustomerAPIKeys(w http.ResponseWriter, r *http.Request) {
+	id, err := strconv.Atoi(r.PathValue("id"))
+	if err != nil {
+		writeError(w, http.StatusBadRequest, "Ungueltige ID")
+		return
+	}
+	keys, err := h.db.ListCustomerAPIKeys(id)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "Laden fehlgeschlagen")
+		return
+	}
+	writeJSON(w, http.StatusOK, keys)
+}
+
 // DELETE /api/v1/apikeys/{id}
 func (h *Handler) deleteAPIKey(w http.ResponseWriter, r *http.Request) {
 	idStr := r.PathValue("id")

backend/api/handlers.go

@@ -59,6 +59,7 @@ func (h *Handler) SetupRoutes(mux *http.ServeMux, hub *ws.Hub) {
 	mux.HandleFunc("GET /api/v1/apikeys", h.listAPIKeys)
 	mux.HandleFunc("POST /api/v1/apikeys", h.createAPIKey)
 	mux.HandleFunc("DELETE /api/v1/apikeys/{id}", h.deleteAPIKey)
+	mux.HandleFunc("GET /api/v1/customers/{id}/apikeys", h.listCustomerAPIKeys)
 
 	// System Settings
 	mux.HandleFunc("GET /api/v1/settings", h.getSettings)