Bug Description

The wideArea schema in zod-schema.ts uses .strict() but is missing the domain field. This field is:

1. Defined in the TypeScript type at types.gateway.ts:21 as domain?: string
2. Used across the codebase:
   • cli/gateway-cli/register.ts:216 — gateway registration
   • cli/dns-cli.ts:127,131,161 — DNS CLI commands
   • gateway/server-discovery-runtime.ts:66,79 — runtime discovery
   • gateway/server.impl.ts:609 — server implementation
   • commands/gateway-status.ts:42 — status command
   • commands/onboard-remote.ts:85 — remote onboarding

Because the schema is .strict(), users setting discovery.wideArea.domain get a validation error, blocking unicast DNS-SD configuration.

Steps to Reproduce

discovery:
  wideArea:
    enabled: true
    domain: "openclaw.internal"

This config is rejected by validateConfigObject().

Root Cause

Type/schema drift: domain was added to the type and runtime code but not to the Zod schema.