Is your feature request related to a problem? Please describe.

• Yes. In Console v3 Naming service detail, instance deletion was missing
• The Console instance API only supported list and update, but not delete
• Because of this, users could not deregister instances directly from the Console UI

Describe the solution you'd like
Add full instance delete support in Console v3:

• Add DELETE /v3/console/ns/instance in Console instance controller with Console API permission (WRITE)
• Extend instance handling chain in console backend:
  • InstanceHandler adds removeInstance
  • Proxy forwards removeInstance
  • Inner handler uses naming remove logic
  • Remote handler delegates to maintainer client deregister logic
  • Noop handler keeps consistent behavior when naming is disabled
• Add/extend backend unit tests for controller/proxy/handler delete flow
• Add frontend support in Console UI Next:
  • API method for DELETE /v3/console/ns/instance
  • Delete action button in service detail instance table
  • Confirmation dialog before deletion
  • Refresh instance list after success (including pagination fallback)
  • i18n messages for zh-CN and en-US

Describe alternatives you've considered

• Calling /v3/admin/ns/instance directly from frontend: rejected due to API boundary and Console architecture expectations
• Keeping only online/offline without delete: rejected because users still need real deregistration
• Manual API calls via scripts/curl: works as workaround but not acceptable as normal Console UX

Additional context

• Scope: console + console-ui-next only
• API added: DELETE /v3/console/ns/instance
• This aligns with the documented limitation and closes the missing capability on the Console instance page
• Focused backend tests for the new delete chain are already prepared and passing locally