- SSID input: add autocorrect=off, autocapitalize=none, spellcheck=false to
prevent mobile browsers from silently altering SSIDs with special chars
- Password input: same attrs for consistency
- Firmware: accept WPA/WPA2 mixed mode (WIFI_AUTH_WPA_WPA2_PSK) so networks
with special characters in the password connect regardless of WPA version
- Firmware: detect open networks (empty password) and use WIFI_AUTH_OPEN so
passwordless networks are not rejected by the auth threshold
JSON encoding path (JSON.stringify → TextEncoderStream → cJSON) already
handles all characters correctly; these changes prevent browser-side mangling
and firmware-side connection rejection.