refactor: flatpak management goes both ways now

config/ansible/tasks/flatpaks.yml

@@ -4,11 +4,14 @@
     flatpakrepo_url: https://flathub.org/repo/flathub.flatpakrepo
     state: present
 
-- name: Install Flatpak applications
-  community.general.flatpak:
-    name: "{{ item }}"
-    state: present
-  loop:
+- name: Get list of installed Flatpaks
+  command: flatpak list --app --columns=application
+  register: installed_flatpaks
+  changed_when: false
+
+- name: Define desired Flatpaks
+  set_fact:
+    desired_flatpaks:
       - org.fkoehler.KTailctl
       - org.mozilla.Thunderbird
       - io.github.kukuruzka165.materialgram
@@ -47,3 +50,15 @@
       - io.github.nokse22.Exhibit
       - net.nokyan.Resources
       - dev.zed.Zed
+
+- name: Install desired Flatpak applications
+  community.general.flatpak:
+    name: "{{ item }}"
+    state: present
+  loop: "{{ desired_flatpaks }}"
+
+- name: Remove undesired Flatpak applications
+  community.general.flatpak:
+    name: "{{ item }}"
+    state: absent
+  loop: "{{ installed_flatpaks.stdout_lines | difference(desired_flatpaks) }}"