Fix transmission config to prevent perpetual ansible diffs

- Expand settings.json template to include all transmission defaults
- Use static pre-hashed rpc-password so transmission doesn't regenerate
- Change file mode from 0644 to 0600 to match transmission's default
- Add Jinja comment explaining the RPC password workaround

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ansible/roles/transmission/tasks/main.yml

@@ -27,7 +27,7 @@
   ansible.builtin.template:
     src: settings.json.j2
     dest: "{{ transmission_config_dir }}/settings.json"
-    mode: '0644'
+    mode: '0600'
   check_mode: true
   register: settings_check
 
@@ -42,7 +42,7 @@
   ansible.builtin.template:
     src: settings.json.j2
     dest: "{{ transmission_config_dir }}/settings.json"
-    mode: '0644'
+    mode: '0600'
   notify: restart transmission
 
 - name: Ensure transmission service is started