docs(go): add Qwen3.8 Max

[MrMushrooooom]

Summary

• add Qwen3.8 Max to the Go landing and workspace model lists
• add Qwen3.8 Max to the limits graph with $15 usage estimates
• document pricing, request estimates, endpoints, and privacy across all locales
• correct stale Qwen3.7 Max request estimates

Verification

• bun typecheck in packages/console/app
• bun run build in packages/web
• production Go model discovery and generation through Anthropic and OpenAI-compatible endpoints