fix: dropbear: Pull the ed25519 pubkey from $HOME, not /home/$USER

Also, pin the mode so it's never world-writable.

roles/config/tasks/main.yml

@@ -25,9 +25,10 @@
 - name: Update authorized keys
   lineinfile:
     path: /etc/dropbear/authorized_keys
-    line: "{{ lookup('file', '/home/' + lookup('env', 'USER') + '/.ssh/id_ed25519.pub') }}"
+    line: "{{ lookup('file', lookup('env', 'HOME') + '/.ssh/id_ed25519.pub') }}"
     state: present
     create: yes
+    mode: 644
 
 - name: Disable Root password authentication
   uci: