feat: Replace Playwright MCP with agent-browser CLI

- Remove Playwright MCP server from plugin
- Add new agent-browser skill for CLI-based browser automation
- Rename /playwright-test to /test-browser command
- Update all commands and agents to use agent-browser CLI
- Update README and plugin.json

agent-browser is Vercel's headless browser CLI designed for AI agents.
It uses ref-based selection (@e1, @e2) from accessibility snapshots
and provides a simpler CLI interface compared to MCP tools.

Key benefits:
- No MCP server required
- Simpler Bash-based workflow
- Same ref-based element selection
- Better for quick automation tasks

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

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

plugins/compound-engineering/commands/workflows/work.md

@@ -181,11 +181,13 @@ This command takes a work document (plan, specification, or todo file) and execu
    bin/dev  # Run in background
    ```
 
-   **Step 2: Capture screenshots with Playwright MCP tools**
-   - `browser_navigate` to go to affected pages
-   - `browser_resize` to set viewport (desktop or mobile as needed)
-   - `browser_snapshot` to verify page state
-   - `browser_take_screenshot` to capture images
+   **Step 2: Capture screenshots with agent-browser CLI**
+   ```bash
+   agent-browser open http://localhost:3000/[route]
+   agent-browser snapshot -i
+   agent-browser screenshot output.png
+   ```
+   See the `agent-browser` skill for detailed usage.
 
    **Step 3: Upload using imgup skill**
    ```bash