Add README and setup documentation for Greptile plugin

- Add README.md with setup instructions for getting API key
- Document the GREPTILE_API_KEY environment variable requirement
- Add homepage, author URL, and keywords to plugin.json
- List available capabilities (code search, PR management, code reviews)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: dakshgup

external_plugins/greptile/.claude-plugin/plugin.json

@@ -2,6 +2,9 @@
   "name": "greptile",
   "description": "AI-powered codebase search and understanding. Query your repositories using natural language to find relevant code, understand dependencies, and get contextual answers about your codebase architecture.",
   "author": {
-    "name": "Greptile"
-  }
+    "name": "Greptile",
+    "url": "https://greptile.com"
+  },
+  "homepage": "https://docs.greptile.com",
+  "keywords": ["code-search", "code-review", "ai", "codebase", "pull-requests"]
 }

external_plugins/greptile/README.md

@@ -0,0 +1,39 @@
+# Greptile
+
+AI-powered codebase search and understanding for Claude Code. Query your repositories using natural language to find relevant code, understand dependencies, and get contextual answers about your codebase architecture.
+
+## Setup
+
+### 1. Create a Greptile Account
+
+Sign up at [greptile.com](https://greptile.com) and connect your repositories.
+
+### 2. Get Your API Key
+
+1. Go to [API Settings](https://app.greptile.com/settings/api)
+2. Generate a new API key
+3. Copy the key
+
+### 3. Set Environment Variable
+
+Add to your shell profile (`.bashrc`, `.zshrc`, etc.):
+
+```bash
+export GREPTILE_API_KEY="your-api-key-here"
+```
+
+Then reload your shell or run `source ~/.zshrc`.
+
+## Capabilities
+
+Once configured, this plugin provides tools to:
+
+- **Search code** - Find relevant code across your repositories using natural language
+- **List pull requests** - View and filter PRs by repository, author, or status
+- **Get PR details** - See PR metadata, statistics, and review comments
+- **Trigger code reviews** - Request AI-powered code reviews on PRs
+- **Manage custom context** - Create and search organization-specific coding guidelines
+
+## Documentation
+
+For more information, visit [docs.greptile.com](https://docs.greptile.com).