Polish before first GitHub push: consistent adapter usage and naming

stability_watchdog.sh mover check now uses platform_is_mover_running()
instead of raw pgrep, matching server_reboot.sh.

check_unraid_version_parity() renamed to check_os_version_parity() —
the function internals were already platform-neutral after the adapter
refactor; the name was the last Unraid artifact.

common.sh

@@ -80,7 +80,7 @@
 #
 #
 #            Three new safety functions added:
-#            check_unraid_version_parity() — refuses remote ops on version mismatch
+#            check_os_version_parity() — refuses remote ops on version mismatch
 #              reads OS version via platform_get_os_version() / platform_os_version_probe_cmd()
 #              major mismatch → abort | minor mismatch → configurable warn/abort
 #            check_remote_docker_daemon() — verifies remote Docker daemon before
@@ -1748,9 +1748,9 @@ check_api() {
 #   "abort" — exit the calling script (default for major version differences)
 #   Major version mismatch always aborts regardless of setting
 #
-# Usage: check_unraid_version_parity || exit 1
+# Usage: check_os_version_parity || exit 1
 
-check_unraid_version_parity() {
+check_os_version_parity() {
     local local_version remote_version
 
     # Read local version