OpenAI issues keys with sk-None- prefix in both short (56 char) and long
(130+ char) formats. The existing openai.2 rule only matches long keys
with {100,} minimum length. This adds openai.3 to detect the short variant:
sk-None- followed by exactly 48 alphanumeric characters.
Fixes detection gap where trufflehog found valid keys that kingfisher missed.
Why: Hyperscan doesn’t support lookaheads/behinds, so many “must contain X and Y” checks had to be baked into the regex (hurting readability) or were impossible. pattern_requirements applies lightweight, in-memory checks after a match is found, keeping patterns fast and clean.
