Fix VPS replica clusters: match home's max_connections (recovery abort)

Postgres refuses to replay WAL past a checkpoint recorded with higher
max_connections/max_wal_senders/etc than the recovering instance's own
settings: 'recovery aborted because of insufficient parameter settings:
max_connections = 100 is a lower setting than on the primary server,
where its value was 200' - confirmed live on all 3 VPS clusters (they
had no postgresql.parameters block at all, defaulting to CNPG's 100).
Copied home's full postgresql.parameters block to remove any other
potential mismatch (max_wal_senders, max_worker_processes are subject
to the same check). Bumped memory requests/limits to match home too -
shared_buffers: 512MB needs headroom the previous 256Mi/1Gi didn't have.

infrastructure/vps-standby/nextcloud/manifests/cnpg-cluster.yaml

@@ -19,18 +19,36 @@ spec:
   imageName: ghcr.io/cloudnative-pg/postgresql:16
   instances: 1
 
+  # shared_buffers: 512MB above needs headroom - matches home's requests/limits.
   resources:
     requests:
-      memory: "256Mi"
+      memory: "512Mi"
       cpu: "25m"
     limits:
-      memory: "1Gi"
+      memory: "2Gi"
       cpu: "250m"
 
   storage:
     size: 20Gi
     storageClass: local-path
 
+  # See infrastructure/vps-standby/authentik/manifests/cnpg-cluster.yaml
+  # for why this must match home's settings (recovery aborts otherwise).
+  postgresql:
+    parameters:
+      max_connections: "200"
+      shared_buffers: "512MB"
+      effective_cache_size: "1536MB"
+      maintenance_work_mem: "128MB"
+      checkpoint_completion_target: "0.9"
+      wal_buffers: "16MB"
+      default_statistics_target: "100"
+      random_page_cost: "1.1"
+      effective_io_concurrency: "200"
+      work_mem: "2621kB"
+      min_wal_size: "1GB"
+      max_wal_size: "4GB"
+
   bootstrap:
     recovery:
       source: home-backup