Fix backend patch never loading at boot: schedule deferred middlewared restart

PREINIT initshutdownscripts are executed by middlewared itself
(ix-preinit.service, ordered after ix-zfs pool import), so the running
process had already imported the stock modules when apply.sh patched
them in the overlay — S3/B2 support silently reverted on every reboot
until something restarted middlewared. install.sh masked the bug with
its explicit restart.

apply.sh now detects boot context (parent process is middlewared) and
schedules a single detached restart via a transient systemd unit
(truecloud-mw-restart, After=multi-user.target and ix-postinit.service).
Manual runs never trigger a restart.

create_task.py verify no longer trusts hook_status.json alone: it
compares the middlewared main-process start time (derived from
/proc/<pid>/stat and btime) against patched_at and reports FAIL when
the running process predates the patch.

recover.sh and uninstall.sh cancel a still-queued deferred restart
before their own; docs updated to match the real boot ordering.

uninstall.sh

@@ -3,7 +3,7 @@
 
 set -euo pipefail
 
-VERSION="0.0.3"
+VERSION="0.0.4"
 
 PATCH_DIR="$(cd "$(dirname "$0")" && pwd)"
 _HOOK_COMMENT='TrueCloud provider patch (S3/B2)'
@@ -99,6 +99,10 @@ if [ "$_restore_failed" -eq 1 ]; then
     exit 1
 fi
 
+# Cancel a deferred boot restart if one is still queued — we restart ourselves.
+systemctl stop truecloud-mw-restart.service 2>/dev/null || true
+systemctl reset-failed truecloud-mw-restart.service 2>/dev/null || true
+
 echo "Restarting middlewared ..."
 if systemctl restart middlewared; then
     echo ""