refactor!: replace sys-systemctl with sys-service, add sys-daemon, and rename systemctl_* → system_service_* across repo

- Swap role includes: sys-systemctl → sys-service in all roles
- Rename variables everywhere: systemctl_* → system_service_* (incl. systemctl_id → system_service_id)
- Templates: ExecStart now uses {{ system_service_script_exec }}; add optional RuntimeMaxSec via SYS_SERVICE_DEFAULT_RUNTIME
- Move SYS_SERVICE defaults into roles/sys-service/defaults (remove SYS_SERVICE_ALL_ENABLED & SYS_SERVICE_DEFAULT_STATE from group_vars/07_services.yml)
- Tidy group_vars/all/08_timer.yml formatting
- Introduce roles/sys-daemon:
  - default manager timeouts (timeouts.conf)
  - optional purge of /etc/systemd/system.conf.d
  - validation via systemd-analyze verify
  - handlers for daemon-reload & daemon-reexec
- Refactor sys-timer to system_service_* variables (docs and templates updated)
- Move filter_plugins/filetype.py under sys-service
- Update meta/README to point to official systemd docs
- Touch many roles (backup/cleanup/health/repair/certs/nginx/csp/wireguard/ssd-hdd/keyboard/update-docker/alarm compose/email/telegram/etc.) to new naming

BREAKING CHANGE:
- Role path/name change: use `sys-service` instead of `sys-systemctl`
- All `systemctl_*` vars are now `system_service_*` (e.g., on_calendar, state, timer_enabled, script_exec, id)
- If you have custom templates, adopt RuntimeMaxSec and new variable names

Chat context: https://chatgpt.com/share/68a47568-312c-800f-af3f-e98575446327

roles/sys-daemon/tasks/01_reset.yml

@@ -0,0 +1,16 @@
+- name: reload system daemon
+  command: /bin/true
+  notify: "reload system daemon"
+
+- name: "Sanity check SYSTEMD_MANAGER_CONF_DIR"
+  assert:
+    that:
+      - SYSTEMD_MANAGER_CONF_DIR | regex_search('^/etc/systemd/system\.conf\.d/?$')
+    fail_msg: "SYSTEMD_MANAGER_CONF_DIR must be /etc/systemd/system.conf.d"
+  when: SYSTEMD_MANAGER_RESET_PURGE | bool
+
+- name: "Purge manager drop-in directory (remove)"
+  file:
+    path: "{{ SYSTEMD_MANAGER_CONF_DIR }}"
+    state: absent
+  notify: reexec systemd manager