WiFi: add WPA3/SAE authentication frame helpers

[Akindotcome]

Motivation
WPA3 introduces the Simultaneous Authentication of Equals (SAE) handshake for Wi-Fi. Scapy previously lacked simple builders and predicates for crafting SAE commit/confirm frames. This patch adds lightweight helpers to simplify WPA3/SAE testing and pcap crafting without implementing crypto.

Design

• New module: scapy/modules/wifi_sae.py
  • sae_commit_frame() / sae_confirm_frame() to build SAE Authentication frames
  • Predicates: is_sae_auth(), sae_is_commit(), sae_is_confirm()
  • get_sae_payload() to extract raw SAE payload
• Does not touch dissector hot paths, only frame construction utilities.
• Minimal Radiotap wrapping for injection support.

Tests

• Added test/test_wifi_sae.py and test/test_wpa3_sae.py
• Validates frame fields, predicates, and payload extraction.
• CI: pytest passes locally (4 tests total), and tox -e flake8 is clean.

[gpotter2]

Hi & thanks a lot for the PR !

I'm not super convinced that this PR brings a lot of value. It creates functions over tasks that are very simple (stacking 1 or 2 802.11 layers) that I feel most people will not use (or know that those functions exist).

It's very cool that you are using this ! But as of right know I don't feel like this should be merged.
Thanks again for contributing !

[Akindotcome]

@gpotter2
Thanks a lot for taking the time to review...

I understand your concern - the helpers indeed wrap simple 802.11 constructs, but the motivation was mainly ergonomics and discoverability.
In practice, many users who are exploring WPA3/SAE don’t know which Dot11Auth fields to set, or which seqnum values correspond to Commit vs Confirm. By having small, explicit helpers, it becomes easier to:

• avoid mistakes in frame crafting (algo=8, seqnum=1/2)
• write more readable tests or teaching examples
• provide a clear entry point when someone searches “SAE” inside Scapy

That said, I totally get that you want to keep Scapy lean and avoid niche wrappers that few people might use. If you prefer, I can:

• move these helpers under contrib/ instead of core modules,
• or keep the tests/docs in my fork so others experimenting with WPA3 can still benefit.

Thanks again for your feedback and for maintaining this project — even if this PR doesn’t get merged, it was a great learning experience working with Scapy!