feat(k8s): add Kubernetes Helm chart for emailks service

- Create Helm chart structure with Chart.yaml and values.yaml
- Add deployment template with container configuration and environment variables
- Implement service template for gRPC port exposure
- Add service account template with security configuration
- Include horizontal pod autoscaler template for scaling capabilities
- Add helper templates for naming and label management
- Configure SMTP settings as configurable parameters in values.yaml
- Set up resource limits and requests for container performance
- Implement liveness and readiness probes for health checks
- Add support for existing secrets and custom configurations

charts/templates/_helpers.tpl

@@ -0,0 +1,38 @@
+{{- define "emailks.name" -}}
+{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" }}
+{{- end }}
+
+{{- define "emailks.fullname" -}}
+{{- if .Values.fullnameOverride }}
+{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" }}
+{{- else }}
+{{- $name := default .Chart.Name .Values.nameOverride }}
+{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" }}
+{{- end }}
+{{- end }}
+
+{{- define "emailks.chart" -}}
+{{- printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 | trimSuffix "-" }}
+{{- end }}
+
+{{- define "emailks.labels" -}}
+helm.sh/chart: {{ include "emailks.chart" . }}
+{{ include "emailks.selectorLabels" . }}
+{{- if .Chart.AppVersion }}
+app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
+{{- end }}
+app.kubernetes.io/managed-by: {{ .Release.Service }}
+{{- end }}
+
+{{- define "emailks.selectorLabels" -}}
+app.kubernetes.io/name: {{ include "emailks.name" . }}
+app.kubernetes.io/instance: {{ .Release.Name }}
+{{- end }}
+
+{{- define "emailks.serviceAccountName" -}}
+{{- if .Values.serviceAccount.create }}
+{{- default (include "emailks.fullname" .) .Values.serviceAccount.name }}
+{{- else }}
+{{- default "default" .Values.serviceAccount.name }}
+{{- end }}
+{{- end }}