fix(ha-test): remove Debian LVM handlers and fix corosync authkey length

- Remove before/after-resync-target LVM handlers (snapshot-resync-target-lvm.sh
  doesn't exist in NixOS; exit code 127 caused DRBD to drop connections on sync)
- Remove split-brain handler pointing to /usr/lib/drbd/ (Debian path)
- Fix testAuthKey from 126 to 128 bytes (corosync minimum is 1024 bits)
- Fix cluster-init.sh quorum check: corosync-quorumtool has no -q flag;
  use -s | grep 'Quorate: Yes' instead

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HaH1cSGvhogRP5ExoF6nD8

test-lab/ha/common.nix

@@ -8,9 +8,9 @@ let
   node2Ip = "192.168.2.201";
   drbdPort = 7789;
 
-  # Test-only corosync authkey (128 bytes minimum).
+  # Test-only corosync authkey (128 bytes = 1024 bits minimum for corosync).
   # Not secret — this is a disposable test cluster, not production.
-  testAuthKey = "ha-test-cluster-auth-key-NOT-FOR-PRODUCTION-use-corosync-keygen-for-real-clusters-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
+  testAuthKey = "ha-test-cluster-auth-key-NOT-FOR-PRODUCTION-use-corosync-keygen-for-real-clusters-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
 
   # OCF agent path (from pacemaker's --with-ocfdir).
   # We expose this on PATH so custom scripts can find each other.
@@ -97,11 +97,9 @@ in
         fencing resource-only;
       }
       handlers {
-        # Called by DRBD when a split-brain is detected and this node is
-        # in the secondary role — notifies pacemaker to fence the split node.
-        split-brain "/usr/lib/drbd/notify-split-brain.sh root";
-        before-resync-target "/usr/lib/drbd/snapshot-resync-target-lvm.sh -p 15 -- -c 16k";
-        after-resync-target "/usr/lib/drbd/unsnapshot-resync-target-lvm.sh";
+        # NOTE: LVM-specific before/after-resync-target handlers omitted
+        # (raw /dev/sdb, no LVM). split-brain handler also omitted —
+        # Pacemaker STONITH manages split-brain fencing for the test cluster.
       }
     }