feat(wayland): Add display manager greetd and greeter tuigreet

Sets up a login screen using tuigreet. From there the user is thrown
into a shell. Other units/services (usually, the user service `river`)
take care to start an actual wayland session for the user.

books/templates/greetd-config.toml.j2

@@ -0,0 +1,18 @@
+[terminal]
+# The VT to run the greeter on. Can be "next", "current" or a number
+# designating the VT.
+vt = 7
+
+# The default session, also known as the greeter.
+[default_session]
+command = "tuigreet --cmd zsh"
+user = "{{ greeter_user }}"
+
+# `agreety` is the bundled agetty/login-lookalike. You can replace `/bin/sh`
+# with whatever you want started, such as `sway`.
+# command = "agreety --cmd /bin/sh"
+
+# The user to run the command as. The privileges this user must have depends
+# on the greeter. A graphical greeter may for example require the user to be
+# in the `video` group.
+#user = "_greeter"

books/void_wayland.yaml

@@ -39,6 +39,43 @@
           - xdg-desktop-portal-wlr
         state: present
 
+- name: Set up display manager
+  hosts: target_system
+  become: true
+  vars:
+    greeter_user: _greeter
+  tags:
+    - wayland
+    - greetd
+    - tuigreet
+  tasks:
+    - name: Ensure user group for greeter exists
+      ansible.builtin.group:
+        name: "{{ greeter_user }}"
+        state: present
+
+    - name: Install greetd and tuigreet
+      community.general.xbps:
+        name:
+          - greetd
+          - tuigreet
+        state: present
+
+    - name: Set up tuigreet config for greetd
+      ansible.builtin.template:
+        src: greetd-config.toml.j2
+        dest: "/etc/greetd/config.toml"
+        owner: root
+        group: root
+        mode: 0644
+        force: true
+
+    - name: Activate greetd service
+      ansible.builtin.file:
+        src: "/etc/sv/greetd"
+        dest: "/etc/runit/runsvdir/default/greetd"
+        state: link
+
 - name: Install audio and video for wayland
   hosts: target_system
   become: true