feat: new sway-mode module (#671)

* feat: add sway-mode module

* refactor: Avoid making multiple connections to SwayIPC

Now `sway::Client` is store in `ironbar.clients`, and allow dynamically
registering event listeners, instead of hardcoding events for Workspace
updates.

Remove the use of `swayipc::Connection` from `sway-mode` module, and
replace it with the new event listener system.

#671

docs/_Sidebar.md

@@ -35,6 +35,7 @@
 - [Network Manager](network-manager)
 - [Notifications](notifications)
 - [Script](script)
+- [Sway-mode](sway-mode)
 - [Sys_Info](sys-info)
 - [Tray](tray)
 - [Upower](upower)

docs/modules/Sway-mode.md

@@ -0,0 +1,78 @@
+Displays the current sway mode in a label. If the current sway mode is
+"default", nothing is displayed.
+
+> [!NOTE]
+> This module only works under the [Sway](https://swaywm.org/) compositor.
+
+## Configuration
+
+> Type: `sway-mode`
+
+| Name                  | Type                                        | Default | Description                                                                                                                                           |
+| --------------------- | ------------------------------------------- | ------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `truncate`            | `'start'` or `'middle'` or `'end'` or `Map` | `null`  | The location of the ellipses and where to truncate text from. Leave null to avoid truncating. Use the long-hand `Map` version if specifying a length. |
+| `truncate.mode`       | `'start'` or `'middle'` or `'end'`          | `null`  | The location of the ellipses and where to truncate text from. Leave null to avoid truncating.                                                         |
+| `truncate.length`     | `integer`                                   | `null`  | The fixed width (in chars) of the widget. Leave blank to let GTK automatically handle.                                                                |
+| `truncate.max_length` | `integer`                                   | `null`  | The maximum number of characters before truncating. Leave blank to let GTK automatically handle.                                                      |
+
+<details>
+<summary>JSON</summary>
+
+```json
+{
+  "end": [
+    {
+      "type": "sway-mode",
+      "truncate": "start"
+    }
+  ]
+}
+```
+
+</details>
+
+<details>
+<summary>TOML</summary>
+
+```toml
+[[end]]
+type = "sway-mode"
+truncate = "start"
+```
+
+</details>
+
+<details>
+<summary>YAML</summary>
+
+```yaml
+end:
+  - type: "sway-mode"
+    truncate: "start"
+```
+
+</details>
+
+<details>
+<summary>Corn</summary>
+
+```corn
+{
+  end = [
+    {
+      type = "sway-mode"
+      truncate = "start"
+    }
+  ]
+}
+```
+
+</details>
+
+## Styling
+
+| Selector     | Description            |
+| ------------ | ---------------------- |
+| `.sway_mode` | Sway mode label widget |
+
+For more information on styling, please see the [styling guide](styling-guide).