docs: add PUBLISHING.md — how users install the three plugins

Per-platform install (Claude Code marketplace, Codex install.sh, Copilot MCP
server) plus optional wider-distribution steps (GitHub Release, official Claude
plugin marketplace PR, PyPI) and release-verification commands.

Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>

PUBLISHING.md

@@ -0,0 +1,81 @@
+# Publishing SkillOpt-Sleep — how people install and use it
+
+This is the open-source SkillOpt-Sleep tool: a nightly offline "sleep cycle" for
+local coding agents, shipped as plugins for **Claude Code**, **Codex**, and
+**Copilot**. One engine ([`skillopt_sleep/`](skillopt_sleep)), three thin shells
+([`plugins/`](plugins)), decoupled from the research code.
+
+## How end users install it
+
+### Claude Code
+
+The Claude Code plugin ships a marketplace manifest at
+`plugins/claude-code/.claude-plugin/marketplace.json`.
+
+```text
+# inside Claude Code:
+/plugin marketplace add microsoft/SkillOpt
+/plugin install skillopt-sleep
+/sleep status
+```
+
+(`/plugin marketplace add <owner>/<repo>` reads the marketplace manifest from the
+repo; the entry points at `plugins/claude-code`.)
+
+### Codex
+
+```bash
+git clone https://github.com/microsoft/SkillOpt.git
+cd SkillOpt
+bash plugins/codex/install.sh           # installs /sleep prompt + skill
+export SKILLOPT_SLEEP_REPO="$(pwd)"      # so the runner is found anywhere
+# then, in Codex:  /sleep status
+```
+
+### Copilot
+
+```bash
+git clone https://github.com/microsoft/SkillOpt.git
+# register the MCP server with your Copilot config (see plugins/copilot/README.md
+# and plugins/copilot/mcp-config.example.json), pointing SKILLOPT_SLEEP_REPO at
+# the clone. Then ask Copilot to "run the sleep cycle".
+```
+
+Requirements for all three: Python ≥ 3.10, and the corresponding agent CLI on
+PATH. The default backend is `mock` (no API spend); `--backend claude|codex`
+uses the user's own budget.
+
+## Wider distribution (optional, maintainer steps)
+
+1. **GitHub Release.** Tag the milestone so users can pin a version:
+   ```bash
+   gh release create sleep-v0.1.0 --title "SkillOpt-Sleep v0.1.0" \
+     --notes "Nightly offline self-evolution plugins for Claude Code, Codex, Copilot."
+   ```
+
+2. **Official Claude Code plugin marketplace.** To appear in the public
+   directory, open a PR adding a `marketplace.json` entry to
+   [`anthropics/claude-code` / the official marketplace repo], pointing at
+   `microsoft/SkillOpt` subdir `plugins/claude-code`. Users could then
+   `/plugin install skillopt-sleep@<official-marketplace>`.
+
+3. **PyPI (optional).** `skillopt_sleep` is a standalone package
+   (`pyproject.toml` lists it). A `pip install skillopt-sleep` distribution would
+   let users run `python -m skillopt_sleep ...` without cloning. Build with
+   `python -m build` and publish with `twine`.
+
+4. **README News.** The main [`README.md`](README.md) already announces the
+   release and links to [`plugins/`](plugins) and
+   [`docs/sleep/FINAL_REPORT.md`](docs/sleep/FINAL_REPORT.md).
+
+## Verifying a release works
+
+```bash
+# deterministic, no API key:
+python -m skillopt_sleep.experiments.run_experiment --persona researcher --assert-improves
+# the unit suite:
+python -m unittest tests.test_sleep_engine
+# the MCP server (Copilot):
+printf '%s\n' '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' \
+  | SKILLOPT_SLEEP_REPO="$(pwd)" python3 plugins/copilot/mcp_server.py
+```