fix(ipsec): guard ipsec_encapsulation on ovs-monitor-ipsec liveness

enableOVNIPSec set OVS cert pointers + ipsec_encapsulation=true without
ensuring ovs-monitor-ipsec.service was running. Without that daemon, OVS
holds the cert pointers unused, strongSwan never gets IKE config, and
tunnel traffic ovn-controller marks for encryption gets silently
dropped. TestMultinodeIPSec fails on `node1 xfrm has no AEAD SAs`.

- systemd: spinifex-daemon Wants=/After= ovs-monitor-ipsec.service
- daemon: ensureOVSMonitorIPSecActive — systemctl enable --now +
  is-active poll; refuses to flip ipsec_encapsulation if daemon is dead
- daemon: single-node short-circuit — no peers means no tunnels means
  the flag is at best inert and at worst load-bearing-silent-drop
- ci: capture-net-diag.sh + workflow steps to snapshot OVS/OVN/xfrm
  state on failure, fan out across all 3 multinode nodes

Refs: mulga-siv-136

.github/scripts/capture-net-diag.sh

@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+# capture-net-diag.sh — write a snapshot of network / OVN / OVS / IPsec
+# state into $1 (a directory the caller already created on the local host).
+# Designed to run on a spinifex node after an E2E suite, before tofu destroy
+# pulls the rug out. Every command is independent — `|| true` so a missing
+# binary on one path doesn't abort the rest of the capture.
+#
+# Output layout (under $1/net-diag/):
+#   ovs-monitor-ipsec.status         systemctl status (output-only)
+#   ovs-monitor-ipsec.journal        last 200 journal lines
+#   ipsec.openvswitch_conf           ovs-vsctl get Open_vSwitch . other_config
+#   ipsec.xfrm_state                 ip xfrm state list
+#   ipsec.xfrm_policy                ip xfrm policy list
+#   ovn.sb_show                      ovn-sbctl show
+#   ovn.nb_show                      ovn-nbctl show
+#   ovs.show                         ovs-vsctl show
+#   ovs.flows_br_int                 ovs-ofctl dump-flows br-int
+#   ovs.tunnels                      ovs-appctl ofproto/list-tunnels br-int
+#   net.links                        ip -s link show
+#   net.routes                       ip route show table all
+#   net.addrs                        ip -br addr show
+#   systemd.failed_units             systemctl list-units --state=failed
+set +e
+OUT="${1:?usage: capture-net-diag.sh <output-dir>}"
+mkdir -p "$OUT"
+
+run() {
+    local label="$1"; shift
+    {
+        echo "# $*"
+        "$@" 2>&1
+    } > "$OUT/$label" || true
+}
+
+run ovs-monitor-ipsec.status            sudo systemctl status ovs-monitor-ipsec.service --no-pager --full --lines=50
+run ovs-monitor-ipsec.journal           sudo journalctl -u ovs-monitor-ipsec.service --no-pager --output=short-iso -n 200
+run ipsec.openvswitch_conf              sudo ovs-vsctl get Open_vSwitch . other_config
+run ipsec.xfrm_state                    sudo ip xfrm state list
+run ipsec.xfrm_policy                   sudo ip xfrm policy list
+
+run ovn.sb_show                         sudo ovn-sbctl show
+run ovn.nb_show                         sudo ovn-nbctl show
+run ovn.sb_chassis                      sudo ovn-sbctl list chassis
+
+run ovs.show                            sudo ovs-vsctl show
+run ovs.flows_br_int                    sudo ovs-ofctl dump-flows br-int
+run ovs.tunnels                         sudo ovs-appctl ofproto/list-tunnels br-int
+
+run net.links                           ip -s link show
+run net.routes                          ip route show table all
+run net.addrs                           ip -br addr show
+
+run systemd.failed_units                sudo systemctl list-units --state=failed --no-pager
+
+exit 0

.github/workflows/e2e-go.yml

@@ -277,6 +277,23 @@ jobs:
           echo "rc=${E2E_RC}" >> "$GITHUB_OUTPUT"
           exit 0  # don't fail the step — artifact upload + final gate happen below
 
+      - name: Capture network/IPsec diagnostics on VM
+        if: always()
+        run: |
+          set +e
+          # shellcheck source=/dev/null
+          source "${GITHUB_WORKSPACE}/spinifex/.github/scripts/ci-fmt.sh"
+          SSH_OPTS=(-o StrictHostKeyChecking=no -i "${{ steps.vm.outputs.ssh_key }}")
+          VM=tf-user@${{ steps.vm.outputs.wan_ip }}
+          # Ship the diag script, run it into the VM's ARTIFACT_DIR, leave the
+          # output for the next step's tar to pull down. Captures OVN/OVS/IPsec
+          # state at failure time — before teardown destroys the VM.
+          scp "${SSH_OPTS[@]}" \
+            "${GITHUB_WORKSPACE}/spinifex/.github/scripts/capture-net-diag.sh" \
+            "$VM":/tmp/capture-net-diag.sh
+          ssh "${SSH_OPTS[@]}" "$VM" "bash /tmp/capture-net-diag.sh '${ARTIFACT_DIR}/net-diag'"
+          ok "net diagnostics captured"
+
       - name: Collect artifacts from VM
         if: always()
         run: |
@@ -653,6 +670,42 @@ jobs:
           echo "rc=${E2E_RC}" >> "$GITHUB_OUTPUT"
           exit 0
 
+      - name: Capture network/IPsec diagnostics on all nodes
+        if: always()
+        run: |
+          set +e
+          # shellcheck source=/dev/null
+          source "${GITHUB_WORKSPACE}/spinifex/.github/scripts/ci-fmt.sh"
+          SSH_OPTS=(-o StrictHostKeyChecking=no -i "${{ steps.cluster.outputs.ssh_key }}")
+          # Capture per-node into the node1 ARTIFACT_DIR (where Collect pulls
+          # from). One subdir per node so xfrm SA state is comparable across
+          # peers — critical for diagnosing the IPsec wiring (mulga-siv-136).
+          IFS=',' read -ra NODE_LIST <<< "${{ steps.cluster.outputs.nodes_csv }}"
+          NODE1_IP="${NODE_LIST[0]}"
+          scp "${SSH_OPTS[@]}" \
+            "${GITHUB_WORKSPACE}/spinifex/.github/scripts/capture-net-diag.sh" \
+            tf-user@"$NODE1_IP":/tmp/capture-net-diag.sh
+          for i in "${!NODE_LIST[@]}"; do
+            idx=$((i + 1))
+            ip="${NODE_LIST[$i]}"
+            if [ "$idx" -ne 1 ]; then
+              scp "${SSH_OPTS[@]}" \
+                "${GITHUB_WORKSPACE}/spinifex/.github/scripts/capture-net-diag.sh" \
+                tf-user@"$ip":/tmp/capture-net-diag.sh
+            fi
+            ssh "${SSH_OPTS[@]}" tf-user@"$ip" \
+              "bash /tmp/capture-net-diag.sh '${ARTIFACT_DIR}/net-diag-node${idx}'"
+            # node1 keeps its diag locally; pull node2..N back into node1's
+            # ARTIFACT_DIR so the existing tar-pull below catches everything.
+            if [ "$idx" -ne 1 ]; then
+              ssh "${SSH_OPTS[@]}" tf-user@"$ip" \
+                "tar -C '${ARTIFACT_DIR}' -cf - 'net-diag-node${idx}' 2>/dev/null || true" \
+                | ssh "${SSH_OPTS[@]}" tf-user@"$NODE1_IP" \
+                  "tar -C '${ARTIFACT_DIR}' -xf - 2>/dev/null"
+            fi
+            ok "net diagnostics node${idx} captured"
+          done
+
       - name: Collect artifacts from node1
         if: always()
         run: |
@@ -675,6 +728,13 @@ jobs:
               > "${ARTIFACT_DIR}/spinifex-journal-node${idx}.log" 2>/dev/null
             ok "journal node${idx}: $(wc -l < "${ARTIFACT_DIR}/spinifex-journal-node${idx}.log" 2>/dev/null || echo 0) lines"
           done
+          # ovs-monitor-ipsec journal per node (separate file — bead 136).
+          for i in "${!NODE_LIST[@]}"; do
+            idx=$((i + 1))
+            ip="${NODE_LIST[$i]}"
+            ssh "${SSH_OPTS[@]}" tf-user@"$ip" 'sudo journalctl -u ovs-monitor-ipsec.service --no-pager --output=short-iso --since "60 min ago"' \
+              > "${ARTIFACT_DIR}/ovs-monitor-ipsec-node${idx}.log" 2>/dev/null
+          done
 
       - name: Convert test logs to JUnit XML
         if: always()