Phase 6: utility commands, SKILL.md, AGENTS.md, README.md

- Implement screen_size via xcap Monitor, mouse_position via x11rb
  query_pointer, standalone screenshot with optional annotation,
  launch for spawning detached processes
- Handler dispatchers for get-screen-size, get-mouse-position,
  screenshot, launch
- SKILL.md agent discovery file with allowed-tools frontmatter
- AGENTS.md contributor guidelines for AI agents
- README.md with installation, quick start, architecture overview

README.md

@@ -0,0 +1,53 @@
+# desktop-ctl
+
+Desktop control CLI for AI agents on Linux X11. A single installable binary that gives agents full desktop access: screenshots with window refs, mouse/keyboard input, and window management.
+
+Inspired by [agent-browser](https://github.com/vercel-labs/agent-browser) - but for the full desktop.
+
+## Install
+
+```bash
+cargo install desktop-ctl
+```
+
+System dependencies (Debian/Ubuntu):
+```bash
+sudo apt install libxcb-dev libxrandr-dev libclang-dev
+```
+
+## Quick Start
+
+```bash
+# See the desktop
+desktop-ctl snapshot
+
+# Click a window
+desktop-ctl click @w1
+
+# Type text
+desktop-ctl type "hello world"
+
+# Focus by name
+desktop-ctl focus "firefox"
+```
+
+## Architecture
+
+Client-daemon architecture over Unix sockets (NDJSON wire protocol). The daemon starts automatically on first command and keeps the X11 connection alive for fast repeated calls.
+
+```
+Agent -> desktop-ctl CLI (thin client) -> Unix socket -> desktop-ctl daemon -> X11
+```
+
+## Requirements
+
+- Linux with X11 session
+- Rust 1.75+ (for building)
+
+## Wayland Support
+
+Coming in v0.2. The trait-based backend design means adding Hyprland/Wayland support is a single trait implementation with zero refactoring of the core.
+
+## License
+
+MIT OR Apache-2.0