handshake-capture-c6: production SD gating (SD_IsReady), v1.0.1

- Gate capture on SD_IsReady() after successful SD_Init; avoid false
  'insert SD' when SD.cardType() lies after WiFi on shared SPI with LCD
- SD_Init: LCD CS high, SD.end() on empty card; HandshakeCapture save path
  retries SD_Init before discard
- FAT filename sanitize, discard deadlocks, WPA3 scan labels, docs (README,
  PRODUCTION, IMPROVEMENTS), firmware version 1.0.1

Made-with: Cursor

handshake-capture-c6/WiFi_Scanner.cpp

@@ -3,12 +3,6 @@
 #include "LVGL_Driver.h"
 #include "HandshakeCapture.h"
 
-void WiFiScanner_Init(void) {
-  WiFi.mode(WIFI_STA);
-  WiFi.disconnect(false, true);
-  WiFi.setSleep(false);
-}
-
 void WiFiScanner_Refresh(void) {
   Ui_SetWifiStatus("Scanning...");
   Ui_ClearNetworkList();