docs: optimize README for SEO and discoverability

- Add social badges (stars, forks, install)
- Update subtitle to highlight tool compatibility
- Optimize H2 headers with keywords
- Add links to SKILL.md and SPEC.md
- Add OpenCode compatibility and alternative implementations
- Repository topics updated (7→15, +karpathy, llm-wiki, mcp, rag, etc)
- Description updated with battle-tested metrics

README.md

@@ -1,17 +1,20 @@
 # karpathy-llm-wiki
 
-**One skill to build your own Karpathy-style LLM wiki.**
+**Battle-tested LLM Wiki skill for Claude Code, Cursor & Codex**
 
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE)
+[![GitHub stars](https://img.shields.io/github/stars/Astro-Han/karpathy-llm-wiki?style=social)](https://github.com/Astro-Han/karpathy-llm-wiki)
+[![GitHub forks](https://img.shields.io/github/forks/Astro-Han/karpathy-llm-wiki?style=social)](https://github.com/Astro-Han/karpathy-llm-wiki)
 [![Agent Skills](https://img.shields.io/badge/Agent_Skills-compatible-blue)](https://agentskills.io)
+[![Install](https://img.shields.io/badge/Install-npx_add--skill-green)](https://github.com/Astro-Han/karpathy-llm-wiki#install)
 
 <p align="center">
   <img src="assets/karpathy-tweet.png" alt="Karpathy's tweet about LLM Wiki" width="560">
 </p>
 
-## Battle-Tested
+## Battle-Tested Results
 
-This skill powers a **real knowledge base** that's been in daily use since April 2026:
+This skill powers a **production LLM Wiki** that's been in daily use since April 2026:
 
 | Metric | Count | Growth |
 |--------|-------|--------|
@@ -23,15 +26,15 @@ This skill powers a **real knowledge base** that's been in daily use since April
 
 Top topics: ai-coding-tools (29 articles), ai-research (24), product-design-frameworks (8).
 
-See [examples/](examples/) for real articles, raw sources, and the operation log.
+See [examples/](examples/) for real articles, raw sources, and the operation log. See [SKILL.md](SKILL.md) for the full skill specification.
 
-## Install
+## Quick Install
 
 ```bash
 npx add-skill Astro-Han/karpathy-llm-wiki
 ```
 
-Works with Claude Code, Cursor, Codex, and other tools that support the [Agent Skills](https://agentskills.io) standard.
+Works with Claude Code, Cursor, Codex, and other tools that support the [Agent Skills](https://agentskills.io) standard. See [docs/SPEC.md](docs/SPEC.md) for detailed architecture and design decisions.
 
 ## Quick Start
 
@@ -55,7 +58,7 @@ The skill searches your wiki and answers with citations linking back to your art
 
 The skill checks for broken links, missing index entries, stale cross-references, and reports potential issues.
 
-## How It Works
+## How Your LLM Wiki Works
 
 Inspired by [Karpathy's LLM Wiki idea](https://gist.github.com/karpathy/442a6bf555914893e9891c11519de94f):
 
@@ -85,7 +88,7 @@ Three operations:
 
 The wiki compounds over time. Each new source enriches existing articles, adds cross-references, and flags conflicts.
 
-## Compatibility
+## Tool Compatibility
 
 This skill follows the [agentskills.io](https://agentskills.io) open standard. It works with any LLM coding tool that supports SKILL.md:
 
@@ -94,8 +97,11 @@ This skill follows the [agentskills.io](https://agentskills.io) open standard. I
 | Claude Code | `npx add-skill Astro-Han/karpathy-llm-wiki` |
 | Cursor | `npx add-skill Astro-Han/karpathy-llm-wiki` (auto-converts) |
 | Codex CLI | Copy to `.agents/skills/karpathy-llm-wiki/` |
+| OpenCode | `npx add-skill Astro-Han/karpathy-llm-wiki` |
 | Others | Copy `SKILL.md` + `references/` to your tool's skill directory |
 
+**Alternative implementations**: See [lucasastorian/llmwiki](https://github.com/lucasastorian/llmwiki) (MCP-based web app) and [atomicmemory/llm-wiki-compiler](https://github.com/atomicmemory/llm-wiki-compiler) (CLI compiler) for other approaches to Karpathy's LLM Wiki pattern.
+
 ## Inspired By
 
 This is an unofficial community implementation of the LLM Wiki workflow described in [Karpathy's idea file](https://gist.github.com/karpathy/442a6bf555914893e9891c11519de94f) (April 2026). The core value is a battle-tested set of compilation principles and workflow templates, not the code itself.