Unify restore + DR bootstrap: every remote restore now goes through Ansible

Previously restore_start()'s 'remote' target did its own manual scp+ssh+
restore-k8s-apps.sh dance, entirely separate from the new DR bootstrap
playbook (ansible/dr-bootstrap.yml) — meaning restoring onto a genuinely
empty server would just fail (no namespace/PVC/Deployments, and
restore-k8s-apps.sh assumes those exist). Every "External Machine" restore
now runs the same playbook instead: it's safe for both cases, not just the
empty-server one — create-namespace-if-missing and `kubectl apply` for the
sanitized PVC/Secret/manifests are no-ops against a target that already
has this app running with a matching spec (apply only reconciles
differences, and a backup's own captured manifests are by definition
identical to what's already live) — so "restore onto an existing cluster"
and "restore onto nothing" are the same command now; the playbook's own
checks-then-acts steps decide how much of it actually needs to do
anything.

Three real bugs found getting this working, not just wiring it up blind:

1. dr-bootstrap.yml's `hosts: dr_target` only matches a named inventory
   group — the dynamic single-host inventory app.py builds per-request
   (`-i '<ip>,'`) doesn't create one, so nothing matched and the play
   silently skipped. Changed to `hosts: all`, which both invocation styles
   satisfy.

2. ansible-playbook is a pip console-script installed next to whichever
   python is running — the main pod's system python (no venv there) or
   this server's own venv/bin on the standby. A bare "ansible-playbook" in
   the shelled-out command only resolves on the main pod; the standby's
   venv/bin is never on PATH when its python is invoked directly rather
   than through `activate`, so it'd fail there. Resolved relative to
   sys.executable instead, which is correct in both.

3. Passing connection options via `-e ansible_ssh_common_args='-o
   StrictHostKeyChecking=no ...'` hit a real bug in this ansible-core
   version's SSH connection plugin: its own internal tty-detection
   re-parses that string with a strict argparse and throws "argument -o:
   expected one argument" even for one well-formed -o KEY=VALUE — verified
   directly on the CLI, not a shell-quoting artifact from this code.
   Switched to ANSIBLE_HOST_KEY_CHECKING=False / ANSIBLE_TIMEOUT=15 env
   vars, ansible's own dedicated mechanism for the same effect, which
   bypasses that code path entirely.

Also added ansible-core to requirements.txt (installed automatically by
sync-standby-platform.sh's existing `pip install -r requirements.txt`
step; needs a Jenkins rebuild to reach the main pod's image), and synced
ansible/ to the standby the same way backup/ already was — restore_start()
references dr-bootstrap.yml as a fixed absolute path, and that directory
didn't exist there at all before this.

Verified for real end-to-end: triggered a restore via the standby's
actual web UI (target=remote, localhost:2224 tunnel) — Ansible ran env
checks, found k3s already present, reconciled the namespace/PVC/Secret/
manifests (all no-ops against the live cluster), then restore-k8s-apps.sh
restored the data. n8n on the real main server came back healthy
(healthz ok) with all 11 workflows intact in the restored Postgres DB.

scripts/sync-standby-platform.sh

@@ -44,6 +44,13 @@ LIVE_CONFIG="/root/management-platform/config.py"
 # here to scp across, so mirror it too, not just platform/.
 LOCAL_BACKUP_SRC="/root/CloudOps/backup/"
 VM_BACKUP_DIR="/root/CloudOps/backup"
+
+# Same reason as backup/ above — restore_start() references this as a
+# fixed absolute path (/root/CloudOps/ansible/dr-bootstrap.yml) to drive
+# every "External Machine" restore now, not just true from-scratch DR.
+LOCAL_ANSIBLE_SRC="/root/CloudOps/ansible/"
+VM_ANSIBLE_DIR="/root/CloudOps/ansible"
+
 LOG="/root/CloudOps/scripts/sync-standby-platform.log"
 
 SSH_OPTS="-i $VM_KEY -p $VM_PORT -o StrictHostKeyChecking=no -o ConnectTimeout=15"
@@ -82,6 +89,17 @@ if [ $? -ne 0 ]; then
 fi
 CHANGES="${CHANGES}${BACKUP_CHANGES}"
 
+ssh $SSH_OPTS "$VM_USER@$VM_HOST" "mkdir -p $VM_ANSIBLE_DIR"
+ANSIBLE_CHANGES=$(rsync -a --delete -e "ssh $SSH_OPTS" \
+    --exclude tmp --exclude '*.retry' \
+    --itemize-changes \
+    "$LOCAL_ANSIBLE_SRC" "$VM_USER@$VM_HOST:$VM_ANSIBLE_DIR/" 2>>"$LOG")
+if [ $? -ne 0 ]; then
+    log "❌ rsync of ansible/ failed"
+    exit 1
+fi
+CHANGES="${CHANGES}${ANSIBLE_CHANGES}"
+
 CONFIG_CHANGED=""
 if ! scp $SCP_OPTS "$LIVE_CONFIG" "$VM_USER@$VM_HOST:$VM_DEPLOY_DIR/config.py.new" &>>"$LOG"; then
     log "❌ Could not copy live config.py to VM"