Phase 3: Nostr identity derivation + wifistr service discovery

- Add identity.c/h: HMAC-SHA512 derivation from nsec → npub, STA/AP MAC, SSID, AP IP
- Add nostr_event.c/h: NIP-01 event serialization + Schnorr signing (BIP-340)
- Add geohash.c/h: lat/lon to geohash encoding
- Add wifistr.c/h: kind 38787 event builder + WebSocket publish to Nostr relays
- Update config.c/h: nsec-based identity, Nostr relay/geo config, remove static SSID/IP
- Replace custom mbedTLS wallet with nucula library (libsecp256k1)
- Remove wallet.c/h, wallet_persist.c/h (replaced by nucula_lib component)
- Verified on Board A: derived SSID, captive portal, payment, wallet, wifistr publish

1 files changed, 0 insertions, 53 deletions

diff --git a/main/wallet.h b/main/wallet.h
deleted file mode 100644
index 5089f93..0000000
--- a/main/wallet.h
+++ /dev/null
@@ -1,53 +0,0 @@
-#ifndef WALLET_H
-#define WALLET_H
-
-#include "esp_err.h"
-#include <stdint.h>
-#include <stdbool.h>
-
-#define WALLET_MAX_PROOFS 50
-#define WALLET_MAX_KEYSETS 5
-#define WALLET_KEYSET_ID_LEN 68
-#define WALLET_SECRET_LEN 65
-#define WALLET_SIG_LEN 67
-
-typedef struct {
-    uint64_t amount;
-    char id[WALLET_KEYSET_ID_LEN];
-    char secret[WALLET_SECRET_LEN];
-    char c[WALLET_SIG_LEN];
-} wallet_proof_t;
-
-typedef struct {
-    char id[WALLET_KEYSET_ID_LEN];
-    char public_key_33[67];
-    uint64_t amount;
-    int input_fee_ppk;
-} wallet_keyset_t;
-
-typedef struct {
-    wallet_proof_t proofs[WALLET_MAX_PROOFS];
-    int proof_count;
-    wallet_keyset_t keysets[WALLET_MAX_KEYSETS];
-    int keyset_count;
-    uint64_t balance;
-} wallet_t;
-
-esp_err_t wallet_init(void);
-wallet_t *wallet_get(void);
-uint64_t wallet_balance(void);
-
-esp_err_t wallet_add_proofs(const wallet_proof_t *proofs, int count);
-esp_err_t wallet_remove_proof(int index);
-void wallet_clear(void);
-
-esp_err_t wallet_fetch_keysets(const char *mint_url);
-esp_err_t wallet_swap_proofs(const char *mint_url, int start_index, int count);
-
-esp_err_t wallet_create_token(char *out, size_t out_size, uint64_t amount,
-                               const char *mint_url);
-esp_err_t wallet_send(const char *mint_url, uint64_t amount,
-                       char *token_out, size_t token_out_size);
-
-void wallet_print_status(void);
-#endif