network: fix Local Play with NetworkManager/iwd

[alexryndin]

Summary

• What is the goal of this PR? (e.g. Bump up an emulator version, implement a new feature. )

Fix Local Play, broken since the NetworkManager migration (beb5d8a):

• iwd runs with EnableNetworkConfiguration=false, so the [IPv4] block wifictl wrote into the iwd AP profile was silently ignored and the AP never got an address.
• Switching the interface to AP mode behind NetworkManager cannot work: after nmcli device set managed no iwd's own autoconnect re-associates the station, and NM's iwd backend forces Device.Mode back to station on deactivation paths (reset_mode in nm-device-iwd.c). The result is iwctl ap start-profile failing with "Operation aborted" and NETPLAY_AP never appearing.
• Clients had no way to obtain an address: iwd no longer configures IPs and the netplay AP runs no DHCP server.

Rework Local Play to be NetworkManager-native (NM: IP + lifecycle, iwd: 802.11):

• Host (ID 1): NM wifi connection in AP mode (WPA-PSK, NETPLAY_AP) with a static 192.168.80.1/24.
• Clients (IDs 2-4): NM wifi connection with a static 192.168.80.<id>/24 derived from the local play ID; the SSID must be in the scan cache before connection up, the iwd backend fails activation instantly otherwise.
• Teardown deletes the netplay connection so NM returns the device to the ordinary networks; the normal path also cleans stale netplay profiles.

Testing

• How was this tested? (e.g. Built and tested on specific devices, manual testing steps, URLs for CI/CD build artifacts.)
• Test results: (e.g. Screenshots, logs, performance metrics if applicable.)

Tested on two handhelds running the stock 20260901 image with only wifictl replaced: RG353V (RK3566) as host, RG34XX SP (H700) as client.

• Host: NETPLAY_AP comes up, 192.168.80.1/24 assigned, real clients (the second handheld and a laptop) associate and ping both ways.
• Client: keeps its static 192.168.80.2/24, returns to the ordinary network within a second after the host disappears.
• 5 enable/disable cycles: no stale profiles, station mode and ordinary Wi-Fi restored every time.
• 10MB file transferred between the two handhelds over the netplay network (scp, checksum verified).

Additional Context

• Add any other information that might be helpful for the reviewer (e.g., performance implications, potential risks, specific areas to focus on.)

• Known limitation: the AP channel is fixed by iwd (6, 2.4GHz) because NM's iwd AP activation calls Start(ssid, psk) and does not pass a channel through, and iwd falls back to channel 6 when no profile channel is set (ap_load_config() in iwd's src/ap.c, with an upstream TODO to pick the channel via a survey: https://git.kernel.org/pub/scm/network/wireless/iwd.git/tree/src/ap.c?h=3.10#n3685). The LOCAL NETWORK CHANNEL selector is therefore removed from the frontend (network: persist Local Play ID and drop the unused channel selector emulationstation-next#32).

• Needs the EmulationStation-side fix that persists the local play ID (network: persist Local Play ID and drop the unused channel selector emulationstation-next#32); without it the ID selection reverts to host, as reported in https://www.reddit.com/r/ANBERNIC/comments/1pednpa/rocknix_multiplayer/

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YES — agent assisted (GLM by z.ai, opencode): root-cause analysis, patch and testing driven by the author

[spycat88]

Thanks for looking at this, the only issue I have is that you have removed wifi.adhoc.channel, so you have effectively made the setting redundant in ES as it still exists in ES.

[alexryndin]

@spycat88 Thanks, I looked into this more closely.

With the iwd backend, NM's AP activation calls iwd's Start(ssid, psk) / StartOpen(ssid) and never passes 802-11-wireless.channel through. On the iwd side, Start() builds an in-memory AP config without General/Channel, and ap_load_config() then falls back to channel 6 on 2.4GHz, with an upstream TODO next to it to pick the channel via a survey: https://git.kernel.org/pub/scm/network/wireless/iwd.git/tree/src/ap.c?h=3.10#n3685

So restoring wifi.adhoc.channel in wifictl and putting it into the NM connection would be a silent no-op: e.g. ES could show channel 11 while the AP still starts on channel 6.

For consistency I've instead removed the LOCAL NETWORK CHANNEL selector from the frontend (ROCKNIX/emulationstation-next#32, updated) and kept the Local Play ID persistence. If NM/iwd gains real AP channel control later, the option can be restored together with working backend support.