feat: restructure into a multi-extension plugin framework for Claude Code and agy

Replace the skills-only SSoT (skills/<name>/SKILL.md) with plugins/<name>/,
where a plugin can bundle skills, MCP servers, lifecycle hooks, rules,
commands, and agents. scripts/generate_plugins.py now discovers plugins
from one or more layered --source roots and emits real per-target trees
(dist/claude-code/** + .claude-plugin/marketplace.json, dist/agy/**),
translating hooks.json/mcp.json between Claude Code's and agy's actual
schemas instead of only fanning out flat skill lists.

Adds a private-overlay build path (--source/--private-repo/--out/
--install-local) so a second, non-public repo (PII, tokens, personal-only
plugins) can extend or override the public plugin set without either repo
touching the other's history — private builds default to a gitignored
dist-private/ and never land in tracked output.

Drops install.sh and descriptions.json: both only ever covered skills and
pre-date the native plugin marketplace; both tools now install the plugin
marketplace the documented way (Claude Code's /plugin marketplace add,
agy's plugins.json entries). CI path filters move to plugins/**, and the
workflow gains workflow_dispatch for a manual re-trigger.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014YVWWAnvR5TDQzmfY3RXG9

dist/claude-code/git-publish-workflow/.claude-plugin/plugin.json

@@ -0,0 +1,6 @@
+{
+  "name": "git-publish-workflow",
+  "description": "Automates branching, conventional commits, testing, and PR creation for uncommitted or staged work. Handles both independent and stacked PRs.",
+  "version": "1.2.0",
+  "author": "Rootiest"
+}

dist/claude-code/git-publish-workflow/skills/git-publish-workflow/SKILL.md

@@ -0,0 +1,49 @@
+---
+name: git-publish-workflow
+description: Automates branching, conventional commits, testing, and PR creation for uncommitted or staged work. Handles both independent and stacked PRs.
+version: 1.2.0
+user-invocable: true
+author: Rootiest
+---
+
+# Git Publish & PR Workflow
+
+## **Objective**
+To provide a hands-off, end-to-end automation for moving local changes into a formal Pull Request, ensuring code quality through automated and manual verification steps, while intelligently routing Stacked PRs.
+
+## **Execution Protocol**
+
+### **Phase 1: Scope & Base Determination**
+Before execution, check the local git state:
+1. **Scope Check**: Determine the work boundary:
+   * **Case A (Partial):** If staged changes exist, operate **ONLY** on staged changes.
+   * **Case B (Full):** If no changes are staged, operate on **ALL** modified/untracked files.
+2. **Base Branch Detection**: Identify the currently checked-out branch.
+   * **Independent PR**: If the current branch is `main` (or `master`), the new branch will be based on `main`. The PR target will be `main`.
+   * **Stacked PR**: If the current branch is a feature branch (e.g., `feat-a`), assume the new changes are dependent. The new branch will be created from the current branch. The PR target will be the current feature branch (NOT `main`).
+   * *Safety Check*: If creating a Stacked PR, output a brief terminal message stating: "Detected active feature branch. Stacking new PR on top of `[current-branch-name]`."
+
+### **Phase 2: The "Safe-Commit" Sequence**
+1. **Branching**: Generate a `kebab-case` branch name (e.g., `feat-auth-logic` or `fix-header-css`) based off the branch determined in Phase 1.
+2. **Naming**: Use **Conventional Commits** for the message (e.g., `feat(ui): add logout button`).
+3. **Verification**: 
+   * Identify the project type (e.g., Rust/Cargo, Python/Poetry, Node/NPM).
+   * Run the primary `test`, `lint`, or `build` command.
+   * **Abort Policy**: If verification fails, stop the sequence and report the error. Do not push.
+
+### **Phase 3: Remote Integration**
+1. **Push**: Upload the new branch to `origin`.
+2. **PR Creation**: Open a Pull Request targeting the base branch determined in Phase 1 (either `main` or the parent feature branch).
+3. **Documentation**: Populate the PR description with:
+   * **Summary**: A high-level overview of "Why" and "What."
+   * **Manual Verification Checklist**: Provide a Markdown list (`- [ ]`) of 3-5 tactical steps for a human to verify the change in a live environment.
+
+## **Constraints & Rules**
+* **Atomic Commits**: If multiple distinct features are found in the scope, suggest splitting the work instead of one giant commit.
+* **No Force Push**: Never use `--force` unless explicitly requested in the follow-up prompt.
+* **Clean State**: Ensure the workflow ends with the user on the new branch, not the original branch.
+
+## **Trigger Scenarios**
+* User says: "Ship this."
+* User says: "Make a PR for my current changes."
+* Invoked via `/git-publish-workflow`.