feat: Add --install-shortcut parameter to configure tmux automatically

Adds `autoclaude --install-shortcut` command that:
- Checks if Ctrl+A+A shortcut is already configured in ~/.tmux.conf
- Automatically adds the toggle binding if not present
- Reloads tmux config for immediate effect

This makes it easier for new users to set up keyboard shortcuts without
manual config editing.

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

src/autoclaude/cli.py

@@ -451,6 +451,46 @@ class ClaudeCLI:
             self._add_target(session, window)
             self.print_success(f"Automation enabled for {pane_id}")
 
+    def install_shortcut(self):
+        self.print_header("Installing Autoclaude Keyboard Shortcut")
+
+        tmux_conf = Path.home() / '.tmux.conf'
+
+        if not tmux_conf.exists():
+            self.print_error(f"Tmux config not found: {tmux_conf}")
+            return
+
+        content = tmux_conf.read_text()
+
+        # Check if already configured
+        if 'autoclaude-toggle' in content:
+            self.print_info("Shortcut already configured in ~/.tmux.conf")
+            return
+
+        # Get the full path to autoclaude-toggle script
+        script_path = Path(__file__).parent.parent.parent / '.local' / 'bin' / 'autoclaude-toggle'
+        if not script_path.exists():
+            script_path = Path.home() / '.local' / 'bin' / 'autoclaude-toggle'
+
+        if not script_path.exists():
+            self.print_error(f"autoclaude-toggle script not found")
+            return
+
+        # Add the keybinding to tmux config
+        binding = f'\n# Toggle autoclaude automation for active pane and show status\nbind a run-shell "{script_path}"\n'
+
+        tmux_conf.write_text(content + binding)
+        self.print_success(f"Added Ctrl+A+A shortcut to ~/.tmux.conf")
+        self.print_info("Reload tmux config with: tmux source-file ~/.tmux.conf")
+        self.print_info("Or restart your tmux session")
+
+        # Try to reload tmux config
+        try:
+            subprocess.run(['tmux', 'source-file', str(tmux_conf)], timeout=5, check=True)
+            self.print_success("Tmux config reloaded successfully")
+        except Exception as e:
+            self.print_warning(f"Could not auto-reload tmux: {e}")
+
     def show_help(self):
         self.print_header("Autoclaude - Autonomous Claude Code Control System")
 
@@ -584,9 +624,14 @@ Run without arguments for interactive menu.
     parser.add_argument('command', nargs='?', help='Command to run')
     parser.add_argument('args', nargs='*', help='Command arguments')
     parser.add_argument('--version', action='version', version=f'%(prog)s v{__version__}')
+    parser.add_argument('--install-shortcut', action='store_true', help='Install Ctrl+A+A keyboard shortcut in tmux config')
 
     args = parser.parse_args()
 
+    if args.install_shortcut:
+        cli.install_shortcut()
+        return
+
     if not args.command:
         cli.interactive_menu()
         return