feat: add lifecycle gateway chart component

[vigneshrajsb]

Summary

Adds Helm chart support for running the Lifecycle static sites gateway as its own component.

• Adds a disabled-by-default components.gateway values block with deployment, service, ingress, networkPolicy, PDB, and HPA options.
• Sets gateway defaults for LIFECYCLE_MODE=gateway, port 80, health probes, and conservative resources.
• Fixes component HPA scale target names so component HPAs target their own deployment.
• Tightens PDB and NetworkPolicy selectors to include app.kubernetes.io/component.
• Bumps the lifecycle chart version from 0.9.6 to 0.9.7.

Validation

Passed:

• helm lint charts/lifecycle
• helm template with gateway deployment/service/ingress/HPA/PDB enabled
• git diff --check

Notes:

• helm lint still emits the existing Keycloak Operator CRD informational warning, but reports 0 chart(s) failed.