fix(runner/gcp): correct gke_logs filter and reshape gke_traces BigQuery output

[mayankpande88]

Two parity fixes for the GCP primitives:

• gke_logs: the filter matched resource.type="gce_instance" by zone,
  which returns VM syslog rather than node-pool scaling events. Query
  the GKE cluster-autoscaler-visibility logs instead (k8s_cluster
  resource, project_id + location labels, the autoscaler-visibility
  logName, severity>=DEFAULT), with a zone->region fallback since those
  logs are keyed by the cluster's location (zonal vs regional).

• gke_traces: pass the dataset location (explicit location, else
  derived from zone) in the BigQuery job, and reshape the raw BQ REST
  response ({schema.fields[], rows[].f[].v}) into the
  {data, columns, column_types} envelope the backend warehouse consumer
  expects (mirroring the legacy run_bigquery).

Note: the BigQuery reshape key names mirror the legacy agent; the
agent_warehouse consumer contract should be confirmed against the
backend repo before release.

Co-Authored-By: Claude Opus 4.8 (1M context) noreply@anthropic.com
Claude-Session: https://claude.ai/code/session_01L2HAXQH1gEtX7h4sUJsi9j

[gemini-code-assist]

Code Review

This pull request updates the GCP client to query GKE cluster-autoscaler visibility logs instead of GCE instance logs, implementing a fallback from zone to region when no logs are found. It also updates QueryBigQuery to accept a location parameter and reshape responses into a {data, columns, column_types} envelope. Feedback on these changes includes a correction to zoneToRegion to prevent incorrect truncation of region names (e.g., converting us-central1 to us-central), and a performance optimization to check if cell values are non-empty before unmarshaling them.

[gemini-code-assist]

To avoid unnecessary CPU overhead and potential errors from parsing empty or nil json.RawMessage values, we should check if cell.V is non-empty before calling json.Unmarshal.

Suggested change

	var v any
	// BigQuery cell values are JSON scalars (usually strings); keep the
	// decoded value, or nil on an unexpected shape.
	_ = json.Unmarshal(cell.V, &v)
	vals[i] = v
	var v any
	if len(cell.V) > 0 {
	_ = json.Unmarshal(cell.V, &v)
	}
	vals[i] = v

[github-actions]

📦 Image Tags Updated

I've automatically updated the image tags in `charts/nudgebee-agent/values.yaml` to the latest versions from GHCR for the `main` branch.

The image tags are now synchronized with the latest builds and ready for release.