feat: integrate touchscreen WiFi setup into display UI

- Add DISPLAY_WIFI_SETUP state with full rendering pipeline
- Touch init on display_init(), touch polling in display task
- WiFi scan triggered on setup entry, sorted AP list
- On-screen keyboard for password entry
- Connect result via WiFi event notifications
- Setup button on READY and ERROR screens
- Auto-enter WiFi setup on first boot with no credentials
- Save new WiFi credentials to SPIFFS config.json

1 files changed, 5 insertions, 1 deletions

diff --git a/main/display.h b/main/display.h
index 49b3ffd..e8824b6 100644
--- a/main/display.h
+++ b/main/display.h
@@ -9,7 +9,8 @@ typedef enum {
     DISPLAY_BOOT,
     DISPLAY_READY,
     DISPLAY_PAYMENT_RECEIVED,
-    DISPLAY_ERROR
+    DISPLAY_ERROR,
+    DISPLAY_WIFI_SETUP
 } display_state_t;
 
 typedef enum {
@@ -24,6 +25,9 @@ void display_update(const char *ap_ssid, int active_clients,
                     const char *mint_url, int price_per_step,
                     const char *wifi_status);
 void display_notify_payment(int amount_sats, int64_t allotment_ms);
+void display_notify_wifi_connected(const char *ip);
+void display_notify_wifi_disconnected(void);
+void display_enter_wifi_setup(void);
 void display_render_text(int x, int y, const char *text, uint16_t fg, uint16_t bg, int scale);
 void display_render_qr(const char *text);