Restructure as Claude Code plugin for public distribution

- Added .claude-plugin/plugin.json (name, version, author, keywords)
- Added .claude-plugin/marketplace.json (marketplace catalog)
- Moved SKILL.md + references/ into skills/python-package-development/
- Updated README with plugin install instructions (/plugin marketplace add)
- Users can now install via: /plugin marketplace add Naareman/python-package-development

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Naareman

.claude-plugin/marketplace.json

@@ -0,0 +1,29 @@
+{
+  "name": "python-package-development",
+  "owner": {
+    "name": "Nareman",
+    "url": "https://github.com/Naareman"
+  },
+  "plugins": [
+    {
+      "name": "python-package-development",
+      "source": ".",
+      "description": "Build Python packages the right way — R-inspired philosophy for scaffolding, API design, testing, docs, deprecation lifecycle, and PyPI release using uv, rich, pytest, and mkdocs-material.",
+      "version": "1.0.0",
+      "author": {
+        "name": "Nareman"
+      },
+      "repository": "https://github.com/Naareman/python-package-development",
+      "keywords": [
+        "python",
+        "packaging",
+        "scaffold",
+        "pypi",
+        "uv",
+        "pytest",
+        "mkdocs",
+        "rich"
+      ]
+    }
+  ]
+}

.claude-plugin/plugin.json

@@ -0,0 +1,21 @@
+{
+  "name": "python-package-development",
+  "description": "Build Python packages the right way — R-inspired philosophy for scaffolding, API design, testing, docs, deprecation lifecycle, and PyPI release.",
+  "version": "1.0.0",
+  "author": {
+    "name": "Nareman",
+    "url": "https://github.com/Naareman"
+  },
+  "repository": "https://github.com/Naareman/python-package-development",
+  "license": "MIT",
+  "keywords": [
+    "python",
+    "packaging",
+    "scaffold",
+    "pypi",
+    "uv",
+    "pytest",
+    "mkdocs",
+    "rich"
+  ]
+}

README.md

@@ -4,33 +4,34 @@
 
 ## What is this?
 
-**python-package-development** is a [Claude Code](https://docs.anthropic.com/en/docs/claude-code) skill that teaches Claude how to build Python packages the right way — using the hard-won wisdom of the R package ecosystem.
+**python-package-development** is a [Claude Code](https://docs.anthropic.com/en/docs/claude-code) plugin that teaches Claude how to build Python packages the right way — using the hard-won wisdom of the R package ecosystem.
 
 Python has incredible packages. But it has never had a unified philosophy for *building* them. The R world has one: Hadley Wickham's [*R Packages*](https://r-pkgs.org/) book (with Jenny Bryan), backed by tools like `devtools`, `usethis`, `roxygen2`, `cli`, and `lifecycle`.
 
-This skill translates that philosophy into Python using modern tools: `uv`, `rich`, `pytest`, and `mkdocs-material`.
+This plugin translates that philosophy into Python using modern tools: `uv`, `rich`, `pytest`, and `mkdocs-material`.
 
 > Looking for the CLI tool? See [packright](https://github.com/Naareman/packright) — the companion Python package that automates these conventions from the command line.
 
 ## Installation
 
-### For all your projects (personal scope)
+### Via plugin marketplace (recommended)
 
-```bash
-git clone https://github.com/Naareman/python-package-development.git
-cp -r python-package-development ~/.claude/skills/python-package-development
+```
+/plugin marketplace add Naareman/python-package-development
+/plugin install python-package-development@python-package-development
 ```
 
-### For a single project (project scope)
+### Manual install (personal scope)
 
 ```bash
-mkdir -p .claude/skills
-cp -r /path/to/python-package-development .claude/skills/python-package-development
+git clone https://github.com/Naareman/python-package-development.git
+cp -r python-package-development/skills/python-package-development \
+  ~/.claude/skills/python-package-development
 ```
 
 ### Verify it's installed
 
-In Claude Code, run `/python-package-development` — you should see it in the skill list.
+In Claude Code, type `/python-package-development` — you should see it in the skill list.
 
 ## Usage
 
@@ -87,32 +88,36 @@ Before diving into details, you should see the whole thing working end-to-end.
 | Lifecycle | `lifecycle` package | `warnings` + deprecation conventions |
 | Release | `devtools::release()` | GitHub Actions + PyPI |
 
-## Skill Structure
+## Plugin Structure
 
 ```
 python-package-development/
-├── SKILL.md                          # Main skill definition (philosophy + routing)
-├── README.md                         # This file
+├── .claude-plugin/
+│   ├── plugin.json                   # Plugin metadata
+│   └── marketplace.json              # Marketplace catalog
+├── skills/
+│   └── python-package-development/
+│       ├── SKILL.md                  # Main skill (philosophy + routing)
+│       └── references/
+│           ├── 01-scaffold.md        # Package scaffolding
+│           ├── 02-api-design.md      # Naming, messages, errors
+│           ├── 03-testing.md         # pytest conventions
+│           ├── 04-docs.md            # Docstrings + mkdocs-material
+│           ├── 05-lifecycle.md       # Deprecation ceremony
+│           ├── 06-release.md         # PyPI + GitHub Actions
+│           ├── 07-common-mistakes.md # Anti-patterns
+│           ├── 08-pre-commit.md      # Pre-commit hooks
+│           ├── 09-cli-entry-points.md # CLI entry points
+│           ├── 10-monorepo.md        # Monorepo + namespaces
+│           └── 11-automated-release.md # Automated releases
 ├── examples/
-│   └── my-package/                   # Complete reference implementation (22/22 checks)
-├── references/
-│   ├── 01-scaffold.md                # Package scaffolding (the "whole game")
-│   ├── 02-api-design.md              # Naming, messages, errors
-│   ├── 03-testing.md                 # pytest conventions and patterns
-│   ├── 04-docs.md                    # Docstrings + mkdocs-material
-│   ├── 05-lifecycle.md               # Deprecation ceremony + versioning
-│   ├── 06-release.md                 # PyPI publishing + GitHub Actions
-│   ├── 07-common-mistakes.md         # Python packaging anti-patterns
-│   ├── 08-pre-commit.md              # Pre-commit hooks setup
-│   ├── 09-cli-entry-points.md        # Adding a CLI to your package
-│   ├── 10-monorepo.md                # Monorepo + namespace packages
-│   └── 11-automated-release.md       # Automated version bumps + changelog
+│   └── my-package/                   # Reference implementation (22/22 checks)
 ├── scripts/
 │   ├── count-tokens.py               # Token budget checker
-│   └── check-structure.py            # Audit project against conventions
+│   └── check-structure.py            # Convention audit (22 checks)
 └── .github/
     └── workflows/
-        └── check-budget.yml          # CI: token budget check on PRs
+        └── check-budget.yml          # CI: token budget on PRs
 ```
 
 ## Token Budget
@@ -124,7 +129,7 @@ Follows [posit-dev/skills](https://github.com/posit-dev/skills) (Posit, the comp
 - Reference files: loaded on demand (no hard limit)
 
 ```bash
-python3 scripts/count-tokens.py .
+python3 scripts/count-tokens.py skills/python-package-development/
 ```
 
 ## Contributing