fix(console): proxy migrated model discovery to v1 endpoint

[vimtor]

Summary

• Change the migrated GET /zen/v1/models proxy target from /inference/openai/v1/models to /inference/v1/models.
• One-line path change only; credentials, query strings, streaming, and existing routing behavior remain unchanged.
• Anonymous/unmigrated requests still use the legacy endpoint. Go paths remain untouched.

Dependency and rollout

• Deploy the destination endpoint before this proxy change in each environment.
• Destination is already deployed and checked in dev; production deployment remains pending.
• This proxy change has not been deployed.

Validation

• Legacy Console app typecheck and targeted formatting/diff checks passed.
• Pre-push workspace typecheck passed: 30 tasks.
• No local tests run; no end-to-end legacy proxy verification claimed.