Fix n8n, gitlab, and netbird-operator degraded states

- n8n: Set replicaCount=1 (RWO PVC incompatible with multiple replicas),
  add resource limits to satisfy Kyverno policy
- gitlab: Add ignoreDifferences for redis-gitlab-additional service
  (port names and selectors managed by Redis operator)
- netbird-operator: Add ExternalSecret for netbird-mgmt-api-key in
  netbird namespace and add manifests source to Application

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

apps/n8n/values.yaml

@@ -40,8 +40,8 @@ config:
 secret: {}
 
 # --- Deployment replicas ---
-# Increased to 2 for high availability and faster response times
-replicaCount: 2
+# Single replica required: RWO PVC can't be shared across pods on different nodes
+replicaCount: 1
 
 # --- Service configuration ---
 service:
@@ -72,11 +72,13 @@ persistence:
   size: 10Gi
 
 # --- Resources ---
-# No CPU limits (burst allowed). Keep requests minimal for scheduling.
 resources:
   requests:
     cpu: 100m
     memory: 512Mi
+  limits:
+    cpu: "1"
+    memory: 1Gi
 
 # --- Startup probe ---
 # Allows app to start without being killed by liveness probe