docs: Add documentation for --install-shortcut and keyboard toggle features

Updated README.md and autocode.md to include:
- Installation and usage of --install-shortcut command
- Toggle automation with Ctrl+A+A keyboard shortcut
- New feature highlights in Features section
- Usage examples for keyboard shortcut setup

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

README.md

@@ -13,6 +13,12 @@ pip install -e .
 
 ### Basic Usage
 
+Install keyboard shortcut (one-time setup):
+```bash
+autoclaude --install-shortcut
+```
+This configures `Ctrl+A+A` to toggle automation for the current pane.
+
 List Claude Code sessions:
 ```bash
 autoclaude list
@@ -23,6 +29,12 @@ Start autonomous monitoring:
 autoclaude start main 8
 ```
 
+Toggle automation for active pane:
+```bash
+autoclaude start toggle
+# Or use keyboard shortcut: Ctrl+A+A
+```
+
 Check status:
 ```bash
 autoclaude status
@@ -41,6 +53,10 @@ autoclaude logs
 - Real-time session monitoring
 - Command-line interface for complete control
 - Configuration-driven behavior
+- Keyboard shortcut for quick automation toggle (Ctrl+A+A)
+- One-command setup with `--install-shortcut`
+- Session and window identification in prompt
+- Visual status display in tmux status bar
 
 ## System Requirements