Add @probo/skills multi-agent compliance package

Ship compliance skills and agent plugin wiring for Claude Code,
Codex, OpenCode, and Cursor via Probo MCP (OAuth 2.0). Includes
access-review and missing-signatures workflows, repo-root Git
marketplaces, validation, and npm release CI.

Signed-off-by: Cursor Agent <cursoragent@cursor.com>

Co-authored-by: Bryan FRIMIN <bryan@frimin.fr>

contrib/claude/release/skills.md

@@ -0,0 +1,31 @@
+# Release `@probo/skills`
+
+After confirming commits below, follow the
+[common steps](./README.md#3-common-steps-every-track).
+
+## Track facts
+
+- **Tag pattern**: `@probo/skills/v*`
+- **Version source**: `packages/skills/package.json`
+- **Version bump**: `npm --workspace @probo/skills version <X.Y.Z> --no-git-tag-version`
+- **Validate**: `npm --workspace @probo/skills run validate`
+- **Changelog**: `packages/skills/CHANGELOG.md`
+- **Files to stage**: `packages/skills/package.json`,
+  `packages/skills/CHANGELOG.md`, `package-lock.json`
+- **Workflow**: `.github/workflows/release-npm-skills.yaml`
+- **Path filter**: `packages/skills`
+
+## Detect commits
+
+```shell
+git log $(git describe --tags --abbrev=0 --match='@probo/skills/v*')..HEAD --oneline \
+  -- packages/skills
+```
+
+If empty or non-user-facing only, do not release this track.
+
+## Notes
+
+There is no build step. Run `validate` after the version bump to catch manifest
+or structural errors before tagging. CI runs the same validation, publishes to
+npm with provenance + SBOM, and creates a GitHub Release.