[hyprland/workspaces] Implement workspace taskbars

[pol-rivero]

Summary

This PR expands the functionality of hyprland/workspaces to make it behave more like the wlr/taskbar module. See #2656 for a high-level description.

A full fix of #2656 would require porting those changes to the sway/workspaces module as well. I don't use Sway and I'm not familiar on how it works, but if anyone is interested in giving it a go in a separate PR feel free to ping me and I'll do my best to help.

Config changes

Adds the following changes to the hyprland/workspaces config:

"hyprland/workspaces": {
    // EXISTING SETTINGS
    "format": "{icon}: {windows}", // Used even if "workspace-taskbar.enable" is true
    "format-window-separator": "", // Will be ignored if "workspace-taskbar.enable" is true
    "window-rewrite-default": "",  // Will be ignored if "workspace-taskbar.enable" is true
    "window-rewrite": {},          // Will be ignored if "workspace-taskbar.enable" is true
    // NEW SETTINGS
    "workspace-taskbar": {
        // Enable the workspace taskbar. Default: false
        "enable": true,
        // Format of the windows in the taskbar. Default: "{icon}". Allowed variables: {icon}, {title}
        "format": "{icon} {title:.20}",
        // Icon size in pixels. Default: 16
        "icon-size": 16,
        // Either the name of an installed icon theme or an array of themes (ordered by priority). If not set, the default icon theme is used.
        "icon-theme": "some_icon_theme",
        // Orientation of the taskbar (see screenshots below). Default: "horizontal".
        "orientation": "horizontal"
    }
}

Notice how workspace-taskbar.enable defaults to false, so existing configs shouldn't be affected by these changes without opting in.

What's missing

I'm mainly waiting for your feedback on the config json names and structure. Once that's done I will update the wiki with the finalized spec.

Screenshots

Default CSS, old config file (defaults to old, text-based icons)

"hyprland/workspaces": {
    "format": "{icon}: {windows}",
    "format-window-separator": ",",
    "window-rewrite-default": "?",
    "window-rewrite": {
        "terminator": "",
        "code": "󰨞"
    }
},

---

Default CSS, new config file (default format is just the icon)

"hyprland/workspaces": {
    "format": "{icon}: {windows}",
    "workspace-taskbar": {
        "enable": true
    }
},

---

Default CSS, windows with first 10 chars of title and bigger icon

"hyprland/workspaces": {
    "format": "{icon}: {windows}",
    "workspace-taskbar": {
        "enable": true,
        "format": "{icon} {title:.10}",
        "icon-size": 18
    }
},

---

Tooltip shows full window title. Clicking focuses that specific window

• Note: The screenshot doesn't show my cursor, which was hovering the "Comparing" window.

---

Allows an arbitrary format

"hyprland/workspaces": {
    "format": "[{icon}] (( {windows} ))",
    "workspace-taskbar": {
        "enable": true,
        "format": " [{title:.5} | {icon}] "
    }
},

---

My setup with custom CSS

• Background indicates selected workspace

---

Same CSS as above, vertical orientation

"hyprland/workspaces": {
    "format": "{icon}: {windows}",
    "window-rewrite": {
        "terminator": "",
        "code": "󰨞"
    },
    "workspace-taskbar": {
        "enable": true,
        "format": "{icon} {title:.20}",
        "icon-size": 18,
        "orientation": "vertical"
    }
},