ci: auto-publish skill artifact to tommy0103/obelisk-skill on push to main (Phase 7)

Add a GitHub Actions workflow that builds the readable, non-bundled skill
artifact (`npm run build:skill`) and force-pushes it to the dedicated
tommy0103/obelisk-skill public repo whenever the main branch is updated.
The skill repo is a pure derivative — no manual commits, no PRs; the source
of truth stays in tommy0103/obelisk.

- .github/workflows/publish-skill.yml: checkout → npm ci → build:skill →
  clone skill repo → replace content → commit + force push. Auth via
  SKILL_REPO_DEPLOY_KEY (SSH deploy key with write access to obelisk-skill).
- packaging/skill-README.md: the README placed in the skill repo (install
  instructions + link back to source + "auto-published, don't PR here").
- packaging/skill-LICENSE: MIT license for the skill artifact (relicensed
  from the AGPL-3.0 source by the copyright holder).
- packaging/publish-skill.sh: local convenience script for manual publish.
- packaging/skill-package.json: license field updated to MIT.
- README.md: install command updated to tommy0103/obelisk-skill.
- package.json: add publish:skill script.

The skill repo is MIT-licensed for zero adoption friction (local tool, no
library API, no derivative works expected); the source repo stays AGPL-3.0.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packaging/publish-skill.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SKILL_DIR="dist/obelisk-skill"
+REMOTE="git@github.com:tommy0103/obelisk-skill.git"
+
+if [ ! -d "$SKILL_DIR/scripts" ]; then
+  echo "Error: run 'npm run build:skill' first" >&2
+  exit 1
+fi
+
+cp packaging/skill-README.md "$SKILL_DIR/README.md"
+cp packaging/skill-LICENSE "$SKILL_DIR/LICENSE"
+
+cd "$SKILL_DIR"
+rm -rf .git
+git init
+git remote add origin "$REMOTE"
+git add -A
+git commit -m "publish: $(date -u +%Y-%m-%dT%H:%M:%SZ)"
+git push --force origin HEAD:main

packaging/skill-LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025–2026 tommy0103
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packaging/skill-README.md

@@ -0,0 +1,29 @@
+# Obelisk Skill
+
+Explicit memory infrastructure for coding agents — a queryable SQLite evidence
+layer over local Claude Code and Codex session history.
+
+## Install
+
+```bash
+npx skills add tommy0103/obelisk-skill
+```
+
+Then in any Claude Code session:
+
+```
+/obelisk <your question>
+```
+
+## Source
+
+This repository is **auto-published** from the compiled skill artifact of
+[tommy0103/obelisk](https://github.com/tommy0103/obelisk). Do not open pull
+requests here — contribute to the source repo instead.
+
+## License
+
+MIT — see [LICENSE](LICENSE) in this repository. The
+[source repository](https://github.com/tommy0103/obelisk) is AGPL-3.0; this
+compiled skill artifact is explicitly relicensed under MIT by the copyright
+holder.

packaging/skill-package.json

@@ -3,5 +3,5 @@
   "version": "0.1.0",
   "type": "module",
   "description": "Obelisk skill artifact — readable compiled Core (providers + persist + runtime) over local Claude Code and Codex history. Built by `npm run build:skill`; sources live in the main repo.",
-  "license": "AGPL-3.0"
+  "license": "MIT"
 }