Include MIT notice in individually distributable skill directories

## Problem The official v1.3.1 tree (`24fe0ef7737efae15c87225755e9f6f5965e4888`) has 37 `SKILL.md` directories and the MIT notice at the repository root, but no package-local LICENSE/NOTICE files. A subdirectory-only installation can therefore preserve the complete procedure and its resources without carrying the repository-root notice. For example, `skills/engineering/codebase-design` is individually installable. In Skills Manager 1.42.2, adding the original root LICENSE locally preserves the notice, but a later native same-ID update refuses its removal because upstream does not ship that file in the selected directory. Skills Manager's maintainer closed ancestor-notice propagation as not planned and recommends publishers put the license in the skill's own directory: https://github.com/xingkongliang/skills-manager/issues/572#issuecomment-6317126267 ## Request Would you consider shipping the unchanged root MIT LICENSE inside each independently distributable skill directory, or documenting another supported package-local notice mechanism? This would let subdirectory consumers retain the original notice and follow upstream updates without a locally maintained adaptation. The proposed notice is byte-identical to the root LICENSE; no changes to SKILL.md, resources, authorship claims, or consumer permissions are requested. I have not modified this repository or submitted a patch. A solution at the publisher packaging boundary would be preferable to custom downstream installers.