Phase 5: Lightning auto-payout with LNURL-pay and NUT-05 melt

- New lnurl_pay.c/h: LNURL-pay protocol (GET .well-known/lnurlp + callback)
- New lightning_payout.c/h: threshold-based auto-payout with multi-recipient split
- Extended nucula_wallet bridge with nucula_wallet_melt() (NUT-05)
- Config: payout section with multi-mint, multi-recipient, fee_tolerance
- Default: enabled, TollGate@coinos.io, min_payout=128, min_balance=64
- 18 new unit tests (all passing), 134 total

1 files changed, 4 insertions, 0 deletions

diff --git a/main/config.h b/main/config.h
index 4c6116e..de9f856 100644
--- a/main/config.h
+++ b/main/config.h
@@ -6,6 +6,8 @@
 #include "esp_netif.h"
 #include <stdbool.h>
 
+#include "lightning_payout.h"
+
 #define TOLLGATE_MAX_WIFI_NETWORKS 5
 #define TOLLGATE_MAX_MINT_URLS     3
 #define TOLLGATE_MAX_AP_SSID_LEN   32
@@ -54,6 +56,8 @@ typedef struct {
     int client_steps_to_buy;
     int client_renewal_threshold_pct;
     int client_retry_interval_ms;
+
+    payout_config_t payout;
 } tollgate_config_t;
 
 void tollgate_config_derive_unique(tollgate_config_t *cfg);