feat: initial x3-ssh client

- GTK3 GUI with VTE terminal emulation
- Tabbed SSH sessions
- Server management (add/edit/remove)
- SSH key management (generate/import/delete)
- Quick connect bar
- libssh for SSH connections
- autotools build system (configure && make)

README.md

@@ -0,0 +1,66 @@
+# x3-ssh
+
+A GTK3-based SSH client with a tabbed terminal interface, server management, and SSH key storage.
+
+![Icon](icons/x3-ssh.png)
+
+## Features
+
+- **Tabbed terminal** - Multiple SSH sessions in tabs
+- **Server management** - Save, edit, and remove SSH server configurations
+- **SSH key management** - Generate, import, and manage SSH keys
+- **Quick connect** - Connect directly via host/user/port fields
+- **VTE terminal** - Full terminal emulation with 256 color support
+- **Resizable pty** - Terminal auto-resizes the remote pty on window resize
+
+## Dependencies
+
+- GTK+ 3.0 (>= 3.24)
+- VTE 2.91 (>= 0.50)
+- libssh (>= 0.9)
+- autotools / autoconf / automake / libtool
+- pkg-config
+- g++ with C++17 support
+
+## Building
+
+```bash
+# Install dependencies (Debian/Ubuntu)
+sudo apt install libgtk-3-dev libvte-2.91-dev libssh-dev \
+    autoconf automake libtool pkg-config
+
+# Build
+mkdir -p build-aux
+autoreconf -fi
+./configure
+make
+
+# Install (optional)
+sudo make install
+```
+
+## Configuration
+
+Server configurations are stored in:
+```
+~/.config/sshclient/servers.conf
+```
+
+SSH keys are stored in:
+```
+~/.config/sshclient/keys.conf
+~/.config/sshclient/keys/
+```
+
+## Usage
+
+1. Start the application: `./x3-ssh`
+2. **Quick Connect**: Enter host, user, and port in the toolbar, click "Connect"
+3. **Saved Servers**: Click "Servers" to add/edit/remove saved server configurations
+4. **SSH Keys**: Click "Keys" to generate or import SSH keys
+5. **Tabs**: Click "+ Tab" for a new empty tab, "Close Tab" to close the current one
+6. Select a saved server from the dropdown to auto-fill connection details
+
+## License
+
+MIT