feat: reproducible agent skill collection with install/update tooling

- skills-lock.json pins every skill (extracted from infinito-nexus-core)
- make install (global to $HOME) and make project TARGET=<repo> copy the
  rendered skills into .agents/skills + .claude/skills
- make update refreshes the lock via npx skills; make test validates the
  lock shape and shellchecks the scripts
- CI: test workflow on push/PR, daily update workflow opening a PR
- MIRRORS for code.infinito.nexus and git.veen.world

pyproject.toml

@@ -1,21 +0,0 @@
-[build-system]
-requires = ["setuptools>=68", "wheel"]
-build-backend = "setuptools.build_meta"
-
-[project]
-name = "skills"
-version = "0.1.0"
-description = ""
-readme = "README.md"
-requires-python = ">=3.10"
-authors = [{ name = "Kevin Veen-Birkenbach", email = "kevin@veen.world" }]
-license = { text = "All rights reserved by Kevin Veen-Birkenbach" }
-urls = { Homepage = "https://github.com/kevinveenbirkenbach/skills" }
-
-dependencies = []
-
-[tool.setuptools]
-package-dir = {"" = "src"}
-
-[tool.setuptools.packages.find]
-where = ["src"]