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

README.md

@@ -1,6 +1,20 @@
-# skills
+# skills 🧠
 
-Homepage: https://github.com/kevinveenbirkenbach/skills
+Reproducible agent skill collection, pinned in `skills-lock.json`.
+Works for Claude Code, Codex, Gemini CLI, Cursor, Copilot, Windsurf, Cline, and more.
 
-## Author
-Kevin Veen-Birkenbach <kevin@veen.world>
+Homepage: [github.com/kevinveenbirkenbach/skills](https://github.com/kevinveenbirkenbach/skills)
+
+## Usage 🚀
+
+- `make install` installs the skills globally into your home (`~/.agents/skills` and `~/.claude/skills`).
+- `make project TARGET=/path/to/repo` copies the skills into a project (`<repo>/.agents/skills` and `<repo>/.claude/skills`).
+- `make update` refreshes every skill to its latest version and rewrites `skills-lock.json`.
+- `make test` validates `skills-lock.json` and shellchecks the scripts; CI runs it on every push and after every update.
+
+Node.js is REQUIRED (`npx skills`); `make update` additionally needs `jq`.
+Restart your agent after installing so it loads the new skills.
+
+## Author 👤
+
+Kevin Veen-Birkenbach [kevin@veen.world](mailto:kevin@veen.world)