fix(ha): use drbdmeta --force directly; fix T4 grep-c arithmetic bug

cluster-init.sh: replace 'drbdadm create-md --force' with direct drbdmeta
calls using --force on both steps.  drbdadm create-md --force passes --force
to the create-md sub-call but NOT to write-dev-uuid, which then fails when
/dev/sdb is busy and stdin is not a TTY ("stdin not a TTY, not waiting for
confirmation" → exit 20).  write-dev-uuid failing means DRBD has no UUID,
so the peer can't identify the device → connection fails → no sync → wrong
Active node detected by acceptance tests.

acceptance-tests.sh T4: grep -c returns exit code 1 when the count is 0
(no matches), triggering '|| echo "0"' and producing "0\n0" which breaks
[[ "$IQN_COUNT" -ge 1 ]] with "arithmetic syntax error".  Fixed by running
the pipe inside bash -c with '|| true' on the grep to suppress the
non-zero exit code.  Same fix applied to T5's IQN_ON_STANDBY check.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/ha/cluster-init.sh

@@ -164,13 +164,25 @@ n2_ssh "drbdadm down ha-data 2>/dev/null || true"
 sleep 2
 
 log "Initialising DRBD metadata on $NODE1..."
-if ! drbdadm dstate ha-data 2>/dev/null | grep -q "UpToDate\|Inconsistent\|Diskless"; then
-  drbdadm create-md ha-data --force
+# Use drbdmeta --force directly for BOTH create-md and write-dev-uuid.
+# drbdadm create-md --force passes --force to drbdmeta create-md but NOT to
+# the write-dev-uuid sub-call it makes internally, so write-dev-uuid fails when
+# /dev/sdb is still busy (udev auto-attach, stale DRBD state, etc.) and stdin
+# is not a TTY: "stdin not a TTY, not waiting for confirmation" → exit 20.
+# Calling drbdmeta --force directly bypasses the exclusive-open confirmation on
+# both steps without needing a TTY, regardless of whether the device is busy.
+if ! drbdadm dstate ha-data 2>/dev/null | grep -q "UpToDate"; then
+  UUID1=$(openssl rand -hex 8 2>/dev/null | tr '[:lower:]' '[:upper:]')
+  drbdmeta --force 0 v08 /dev/sdb internal create-md
+  drbdmeta --force 0 v08 /dev/sdb internal write-dev-uuid "$UUID1"
 fi
 
 log "Initialising DRBD metadata on $NODE2..."
-# Use grep -E for ERE alternation inside the remote bash -c string (avoids \| quoting issues).
-n2_ssh "bash -c 'drbdadm dstate ha-data 2>/dev/null | grep -qE \"UpToDate|Inconsistent|Diskless\" || drbdadm create-md ha-data --force'"
+if ! n2_ssh "drbdadm dstate ha-data 2>/dev/null | grep -q UpToDate" 2>/dev/null; then
+  UUID2=$(openssl rand -hex 8 2>/dev/null | tr '[:lower:]' '[:upper:]')
+  n2_ssh "drbdmeta --force 0 v08 /dev/sdb internal create-md"
+  n2_ssh "drbdmeta --force 0 v08 /dev/sdb internal write-dev-uuid '${UUID2}'"
+fi
 
 log "Bringing up DRBD on both nodes..."
 drbdadm up ha-data 2>/dev/null || true