Merge Endpoint Configs

Bulk merge subdomain endpoint configurations.

Adds new subdomains and updates existing ones without deleting any. Use this to bulk-import subdomains from an external system.

Request body: { "configs": { "workspace1": { "api_base_url": "https://workspace1.example.com", "api_auth_config": { "auth_type": "bearer", "token": "sk-abc123" } }, "workspace2": { ... } } }