Increase GKE node size to e2-standard-2 (#513)

## Summary
Bumps the node machine type from e2-small to e2-standard-2 to provide
more CPU and memory headroom for the cluster.

Also disables PodDisruptionBudgets (PDBs) for single-instance PostgreSQL
clusters to prevent node upgrade operations from becoming blocked.

## Changes
- Increase GKE node machine type from e2-small to e2-standard-2
- Set `enablePDB: false` for registry and Grafana PostgreSQL clusters

## Context
The machine type increase addresses resource constraints causing
deployment failures.

The PDB change prevents a specific issue where GKE node upgrades get
stuck when trying to drain nodes containing single-instance PostgreSQL
pods. With `minAvailable: 1` PDBs, evicting the only database instance
violates the availability requirement, blocking the drain operation
indefinitely. Disabling PDBs for these development/staging
single-instance databases allows node maintenance to proceed smoothly.

For production deployments requiring high availability, the instances
count should be increased to 3 with PDBs enabled.

---------

Co-authored-by: Claude <noreply@anthropic.com>

deploy/pkg/providers/gcp/provider.go

@@ -129,7 +129,7 @@ func (p *Provider) CreateCluster(ctx *pulumi.Context, environment string) (*prov
 		// Node pool configuration
 		NodeCount: pulumi.Int(2),
 		NodeConfig: &container.NodePoolNodeConfigArgs{
-			MachineType: pulumi.String("e2-small"),
+			MachineType: pulumi.String("e2-standard-2"),
 			DiskSizeGb:  pulumi.Int(20),
 			DiskType:    pulumi.String("pd-standard"),
 		},