Add soft-ap mode, remove wifi config.

Device defaukts to soft-ap mode. User can use the "WIFI" button to set wifi credentials. Pressing "boot" for 1 second resets to soft-ap mode.

Re-work UI to fill screen.

main/wifi_manager.h

@@ -0,0 +1,16 @@
+#ifndef WIFI_MANAGER_H
+#define WIFI_MANAGER_H
+
+#include "esp_err.h"
+#include "esp_http_server.h"
+
+// Initialize Wi-Fi (Checks NVS, starts AP or STA)
+bool wifi_manager_init_wifi(void);
+
+// Register provisioning URI handlers to the server
+void wifi_manager_register_uri(httpd_handle_t server);
+
+// Helper to erase NVS credentials (can be called by button handler)
+void wifi_manager_erase_config(void);
+
+#endif // WIFI_MANAGER_H