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, 14 insertions, 0 deletions

diff --git a/main/lnurl_pay.h b/main/lnurl_pay.h
new file mode 100644
index 0000000..8969e38
--- /dev/null
+++ b/main/lnurl_pay.h
@@ -0,0 +1,14 @@
+#ifndef LNURL_PAY_H
+#define LNURL_PAY_H
+
+#include "esp_err.h"
+#include <stdint.h>
+#include <stddef.h>
+
+#define LNURL_MAX_BOLT11_LEN 2048
+#define LNURL_MAX_ADDR_LEN   128
+
+esp_err_t lnurl_get_invoice(const char *lightning_address, uint64_t amount_sats,
+                            char *bolt11_out, size_t bolt11_out_size);
+
+#endif