Refactor namespace configuration to use global.namespace

[lanmaoxinqing]

• Replace all .Values.metadata.namespace with .Values.global.namespace across all sub-chart templates
• Remove metadata.namespace configuration from parent and sub-chart values.yaml files
• Update _helpers.tpl files to use .Values.global.namespace for service address generation
• Remove sandbox namespace OSS secret creation from envhub
• Preserve sandboxNamespace configuration for controller pod templates

Changes include:

• deploy/values.yaml: Remove metadata.namespace from all sub-chart configurations
• deploy/api-service/, deploy/controller/, deploy/envhub/, deploy/redis/:
  • Update templates to use .Values.global.namespace
  • Remove metadata.namespace from values.yaml
• deploy/*/templates/_helpers.tpl: Update helper functions to use .Values.global.namespace