fix: preserve v2 proxy routing

[Nomadcxx]

Fixes the startup-order failure found during the bare-metal V2 test.

opencode applies its config-provider transform after package plugins, which can replace the live proxy URL with a stale configured URL. This routes cursor-acp requests through the V2 session.http.request hook, while preserving the request path, method, headers, and body.

Checks:

• build
• unit: 592 pass, 0 fail
• integration: 43 pass, 1 skip, 0 fail
• npm pack --dry-run
• bare-metal opencode V2 run with the default proxy port occupied: exit 0, read tool completed, BAREMETAL_OK returned