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.

Watchdogs/stability_watchdog.sh

@@ -311,7 +311,7 @@ check_abort_conditions() {
         fi
     fi
 
-    if pgrep -f "mover" >/dev/null 2>&1; then
+    if platform_is_mover_running; then
         if [[ "$SYS_WATCHDOG_ABORT_ON_MOVER" == true ]]; then
             error "Mover running — aborting reboot"
             notify "System watchdog aborted reboot on $(hostname) ($MY_ID) — mover running" \