Add AiTells: flags the tells of AI-written prose - #28

Adds AiTells to the library: a style package that flags the mechanical tells of AI-written and spec-grade prose — em-dash habits, epigrams ("is the hero, not a decoration"), abstract-noun triads, virtue tags, clichés, and more. 17 rules: 6 gate as errors, 11 as suggestions.

• Homepage: https://github.com/krishnasunkam/vale-ai-tells
• Zip: attached to releases/latest (v1.0.0), built by a tag-triggered workflow
• Quality: every rule has a fire/stay-silent fixture pair (24 fixtures), plus a labeled mini-bench scoring 100% recall with zero false fires on clean prose; CI runs fixtures, bench, and self-lints the repo's own docs with the package
• tests/ here pass locally with the new entry (structure + keys, including the zip download)

MIT licensed.