feat: add MCP server, headless mode, and OpenClaw skill

- Add proxyclawd-mcp crate: standalone MCP server (rmcp, stdio transport)
  that connects to the proxy web API via WebSocket/REST and exposes 5 tools
  (list_requests, get_request, send_message, get_conversations,
  get_recent_events) and 2 resources (proxy://requests, proxy://status)
- Add --headless flag to run without TUI (requires --web)
- Add openclaw-skill/ with SKILL.md and 4 shell scripts for REST API access
- Set up Cargo workspace with both crates
- Scope CI release builds to -p proxyclawd
- Update README with headless mode, MCP server, and OpenClaw skill docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dyshay

.github/workflows/release.yml

@@ -75,11 +75,11 @@ jobs:
 
       - name: Build with cross
         if: matrix.use_cross
-        run: cross build --release --target ${{ matrix.target }}
+        run: cross build -p proxyclawd --release --target ${{ matrix.target }}
 
       - name: Build with cargo
         if: "!matrix.use_cross"
-        run: cargo build --release --target ${{ matrix.target }}
+        run: cargo build -p proxyclawd --release --target ${{ matrix.target }}
 
       - name: Strip binary (Linux)
         if: runner.os == 'Linux' && !matrix.use_cross