feat: add remote command execution support (#36)

Allow executing commands on remote hosts via 'sshm <host> <command>'.
Add -t/--tty flag for forcing TTY allocation on interactive commands.

Co-authored-by: Guillaume Archambault <67098259+Gu1llaum-3@users.noreply.github.com>

README.md

@@ -229,6 +229,15 @@ sshm
 # Connect directly to a specific host (with history tracking)
 sshm my-server
 
+# Execute a command on a remote host
+sshm my-server uptime
+
+# Execute command with arguments
+sshm my-server ls -la /var/log
+
+# Force TTY allocation for interactive commands
+sshm -t my-server sudo systemctl restart nginx
+
 # Launch TUI with custom SSH config file
 sshm -c /path/to/custom/ssh_config
 
@@ -286,6 +295,33 @@ sshm web-01
 - **Error handling** - Clear messages if host doesn't exist or configuration issues
 - **Config file support** - Works with custom config files using `-c` flag
 
+### Remote Command Execution
+
+Execute commands on remote hosts without opening an interactive shell:
+
+```bash
+# Execute a single command
+sshm prod-server uptime
+
+# Execute command with arguments
+sshm prod-server ls -la /var/log
+
+# Check disk usage
+sshm prod-server df -h
+
+# View logs (pipe to local commands)
+sshm prod-server 'cat /var/log/nginx/access.log' | grep 404
+
+# Force TTY allocation for interactive commands (sudo, vim, etc.)
+sshm -t prod-server sudo systemctl restart nginx
+```
+
+**Features:**
+- **Exit code propagation** - Remote command exit codes are passed through
+- **TTY support** - Use `-t` flag for commands requiring terminal interaction
+- **Pipe-friendly** - Output can be piped to local commands for processing
+- **History tracking** - Command executions are recorded in connection history
+
 ### Backup Configuration
 
 SSHM automatically creates backups of your SSH configuration files before making any changes to ensure your configurations are safe.