Add onboard, forge, notify plugins

[ApurvBazari]

What

Adds three plugins to the curated list:

• onboard — Analyzes existing codebases and generates tailored Claude tooling: CLAUDE.md, path-scoped rules, skills, agents, hooks, and CI/CD. Added to Documentation alongside analyze-codebase and update-claudemd.
• forge — Greenfield project scaffolder. 4-phase wizard, stack-agnostic via web search, walking-skeleton mode, session resume. Added to Development Engineering alongside rapid-prototyper.
• notify — Cross-platform system notifications for Claude Code hooks. macOS (terminal-notifier) and Linux (notify-send). Added to Automation DevOps.

Why

• onboard produces actual Claude artifacts from codebase analysis (most existing tools only recommend).
• forge is an end-to-end greenfield scaffolder that fills a gap in the ecosystem.
• notify is a simple, reliable cross-platform notification helper for hooks.

All three are v1.0+, MIT licensed, documented, and live at https://github.com/ApurvBazari/claude-plugins

Format

Submitted as external-link entries (- [name](url)), matching the pattern used by PR #145 (AgentLint). Happy to vendor the plugins under ./plugins/ instead if that's preferred — let me know.

Checklist

• Entries match existing terse README format
• One entry per plugin, placed in most appropriate category
• MIT licensed
• Tested on macOS and Linux