Add Elixir WiFi example

[mnishiguchi]

Add an Elixir WifiExample that mirrors the Erlang wifi example (STA + AP configuration + SNTP sync) and document it alongside the other Elixir examples.

I tested this example with my ESP32-S3.

The log output looks like this:

Terminal ready
2a0dch (172252) map
I (3134) wifi:ap channel adjust o:1,1 n:11,2
I (3134) wifi:new:<11,0>, old:<1,1>, ap:<11,2>, sta:<11,0>, prof:1, snd_ch_cfg:0x0
I (3134) wifi:state: init -> auth (0xb0)
I (3134) wifi:state: auth -> assoc (0x0)
I (3144) wifi:state: assoc -> run (0x10)
I (3174) wifi:connected with aterm-4dc33e-g, aid = 2, channel 11, BW20, bssid = 1c:7c:98:0c:f7:b6
I (3174) wifi:security: WPA2-PSK, phy: bgn, rssi: -57
I (3174) wifi:pm start, type: 1

I (3174) wifi:dp: 1, bi: 102400, li: 3, scale listen interval from 307200 us to 307200 us
I (3184) wifi:set rx beacon pti, rx_bcn_pti: 0, bcn_timeout: 25000, mt_pti: 0, mt_time: 10000
I (3194) network_driver: WIFI_EVENT_STA_CONNECTED received.
STA connected
I (3214) wifi:AP's beacon interval = 102400 us, DTIM period = 1
I (6694) esp_netif_handlers: sta ip: 192.168.10.125, mask: 255.255.255.0, gw: 192.168.10.1
I (6694) network_driver: IP_EVENT_STA_GOT_IP: 192.168.10.125
Got IP: {{192, 168, 10, 125}, {255, 255, 255, 0}, {192, 168, 10, 1}}
Date: 1970/01/01 00:00:33 (33996ms)
Date: 1970/01/01 00:00:39 (39015ms)
Date: 1970/01/01 00:00:44 (44029ms)
Date: 1970/01/01 00:00:49 (49043ms)
Date: 1970/01/01 00:00:54 (54058ms)
Date: 1970/01/01 00:00:59 (59072ms)
I (35164) network_driver: SNTP_EVENT_BASE_SYNC received.
I (35164) network_driver: Posting SNTP synchronization event
Synchronized time with SNTP server {4596579709683550371, 1070339556}
Date: 2026/01/24 13:27:00 (1769261220953ms)
Date: 2026/01/24 13:27:05 (1769261225968ms)
...

[UncleGrumpy]

Thank you for this contribution! This looks great, and should work just fine on Pico W chips as well as ESP32. I will test soon and make sure, before we have you update the README and adjust verify_platform/1.

[UncleGrumpy]

Just a couple minor details. This will also work for wifi enabled pico devices, just one minor code change needed. Also lets keep the directory and app name consistent with the other Elixir examples.

[UncleGrumpy]

I realize LEDC_Example has doesn't follow the correct naming scheme, I take responsibility for that! I should submit a fix to rename it, and update it to use Elixir IO - AtomVM added support for it since the ledc example was added here.

[UncleGrumpy]

This looks great! Thank you! One last little nit-picky request. Can you flatten (or squash) your commits into a single commit? All of the AtomVM org repos like to keep a clean git history, we do not need the extra review requested changes in the log.

[UncleGrumpy]

Thank you again for the contribution!