[Du] Support split SSID per band in PnP setup flow

[AustinChangLinksys]

Related Issue

• linksys/LinksysWRT#378

Problem

Du ISP routers ship with split SSIDs per band by default (e.g. DULinksys12294-2.4GHz, DULinksys12294-5GHz, DULinksys12294-6GHz). However, the PnP "Personalize your WiFi" step only shows a single SSID/password field, taking the value from the first radio only. The other bands' credentials are not shown or editable during setup.

Expected Behavior

• Unified mode (all bands share the same SSID/password): keep the existing single-field UI.
• Split mode (bands have different SSID/password): show a separate WiFi name/password card per band so each band can be configured independently.

Scope

• SPNM60 (2.4 GHz + 5 GHz)
• SPNM62 (2.4 GHz + 5 GHz + 6 GHz)

Implementation Notes

1. Add PnpWiFiSettings / PnpWiFiRadio model; replace getDefaultWiFiNameAndPassphrase() with getDefaultWiFiSettings() which reads all radios from getRadioInfo and derives split vs unified mode.
2. PersonalWiFiStep renders per-band cards in split mode (validates all bands); unified mode unchanged.
3. save() applies per-band ssid/passphrase in split mode, and re-applies the authoritative per-band security from getRadioInfo to avoid downgrading the network to open (which wiped the passphrase).
4. Pin the horizontal stepper's Back/Next controls below the scrollable content (PrivacyGUI-Widgets v1.2.9) so they stay visible with the taller multi-band content.

Verification

• Factory reset → enter PnP → confirm per-band fields appear in split mode, single field in unified mode.
• Save without editing → passphrase is preserved (security not downgraded).
• Tested on dual-band and tri-band devices.

[AustinChangLinksys]

We found a data consistency issue between JNAP actions on the split-SSID firmware.

Firmware-side issue filed: linksys/LinksysWRT#384

Observation (narrowed down): It is not a general propagation failure. SetSimpleWiFiSettings stores per-band values correctly and GetSimpleWiFiSettings reads them back fine. However, GetRadioInfo3 mis-maps the 6 GHz radio — it returns the 5 GHz SSID instead of the value set for 6 GHz.

Example (after SetSimpleWiFiSettings with 6 GHz = DULinksys00119-12345):

• GetSimpleWiFiSettings → 6 GHz = DULinksys00119-12345 ✅ correct
• GetRadioInfo3 → 6 GHz radio = DULinksys00119 ❌ (shows the 5 GHz SSID)

Why this matters for PnP: The PnP "Personalize your WiFi" step reads per-band WiFi settings from GetRadioInfo3, so the 6 GHz SSID is displayed incorrectly (mirrors 5 GHz) even though it was saved correctly.

GUI options once firmware is clarified:

1. Read per-band WiFi credentials from GetSimpleWiFiSettings (currently correct) instead of GetRadioInfo3, or
2. Wait for the GetRadioInfo3 fix in linksys/LinksysWRT#384.

Test firmware: FW_Pinnacle2.0_v1.2.1.26060821_DU_release.img

@JianrongXiao-Linksys

[AustinChangLinksys]

Implementation

Branch: feat/pnp-split-ssid-support (based on dev-1.2.14), commit 30cdeef1.

Behavior

The PnP "Personalize your WiFi" step now detects whether the router uses unified or split SSIDs and renders accordingly:

• Unified mode (all bands share the same SSID/password): single WiFi name/password field — unchanged from before.
• Split mode (bands have different SSID/password): a separate card per band (2.4 GHz / 5 GHz / 6 GHz), each with its own name/password field and validation.

Changes

• New model PnpWiFiSettings / PnpWiFiRadio (lib/page/instant_setup/data/pnp_wifi_settings.dart). primaryRadio prioritizes the 2.4 GHz band, falling back to the first radio.
• pnp_provider.dart: replaced getDefaultWiFiNameAndPassphrase() with getDefaultWiFiSettings(), which reads all radios from getRadioInfo and derives split vs unified mode (any band's ssid/password differs from the first).
• save(): applies per-band ssid/passphrase in split mode. It always re-applies the authoritative per-band security from getRadioInfo, because getSimpleWiFiSettings can report security: "None" — without this the network would be downgraded to open and the passphrase wiped. isWiFiChanged diffs each band's edited values against the current router values so an untouched form does not trigger a redundant write.
• PersonalWiFiStep (personal_wifi_step.dart): per-band TextEditingControllers created/disposed by mode, all bands validated before enabling Next.
• Call sites (pnp_setup_view.dart, pnp_admin_view.dart) updated to use getDefaultWiFiSettings().primaryRadio.
• Stepper (PrivacyGUI-Widgets v1.2.9): Back/Next controls pinned below the scrollable content so they stay visible with the taller multi-band content.

Known limitation (firmware)

Due to linksys/LinksysWRT#384, GetRadioInfo3 returns the 5 GHz SSID for the 6 GHz band, so the 6 GHz SSID may display incorrectly until the firmware fix lands. The values written via SetSimpleWiFiSettings are correct; only the read-back via GetRadioInfo3 is affected.

Tests

• Updated PnP mock to getDefaultWiFiSettings() and added a split-SSID localization test case (per-band cards screenshot).
• flutter analyze clean (only pre-existing warnings); PnP localization tests pass.