feat: WPA auto-detect from SPIFFS config.json

Parse wifi_auth_mode from config.json to set STA auth threshold.
Defaults to WPA2-PSK (fixes reason=211 with WPA2-only routers).
SPIFFS generated by Makefile auto-detects WPA2/WPA3 from host scan.

Root cause: config.c hardcoded WIFI_AUTH_WPA3_PSK threshold, making
WPA2-only APs invisible during ESP32 scan (reason=211 NO_AP_FOUND).

With this fix, STA connects to WPA2 upstream and Cashu payment
verification works end-to-end.

1 files changed, 2 insertions, 0 deletions

diff --git a/main/config.h b/main/config.h
index b8a3136..173019b 100644
--- a/main/config.h
+++ b/main/config.h
@@ -62,6 +62,8 @@ typedef struct {
 
     payout_config_t payout;
 
+    wifi_auth_mode_t wifi_auth_threshold;
+
     bool cvm_enabled;
     char cvm_relays[256];
 } tollgate_config_t;