feat: multi-mint health tracker, discovery, portal, multi-wallet (Phase 3-8)

- mint_health.h/c: FreeRTOS probing task, GET /v1/info every 5min,
  recovery threshold 3, immediate failure, mutex-protected state
- cashu.c: health-gated acceptance (config match AND reachable)
- tollgate_api.c: one price_per_step tag per reachable mint in discovery
- captive_portal.c: mint list with green/grey indicators, /mints API,
  auto-refresh every 30s via JS
- nucula_wallet.h/cpp: multi-wallet (up to 4), route receive to correct
  wallet by mint URL, balance sums across all wallets
- tollgate_main.c: init health tracker + multi-wallet on service start
- CMakeLists.txt: add mint_health.c

1 files changed, 5 insertions, 2 deletions

diff --git a/main/cashu.c b/main/cashu.c
index 2912d1d..da12ff9 100644
--- a/main/cashu.c
+++ b/main/cashu.c
@@ -1,5 +1,6 @@
 #include "cashu.h"
 #include "config.h"
+#include "mint_health.h"
 #include "esp_log.h"
 #include "esp_http_client.h"
 #include "cJSON.h"
@@ -268,8 +269,10 @@ bool cashu_is_mint_accepted(const char *mint_url)
     if (!mint_url || mint_url[0] == '\0') return false;
     const tollgate_config_t *cfg = tollgate_config_get();
     for (int i = 0; i < cfg->accepted_mint_count; i++) {
-        if (strstr(mint_url, cfg->accepted_mints[i]) != NULL) return true;
-        if (strcmp(mint_url, cfg->accepted_mints[i]) == 0) return true;
+        if (strstr(mint_url, cfg->accepted_mints[i]) != NULL ||
+            strcmp(mint_url, cfg->accepted_mints[i]) == 0) {
+            return mint_health_is_reachable(mint_url);
+        }
     }
     return false;
 }