Add Claude Sonnet 5 support

[SawyerHood]

Summary

• Add claude-sonnet-5 to the Claude Code model catalog with xhigh/ultracode-capable reasoning.
• Update @anthropic-ai/claude-agent-sdk to ^0.3.197 and refresh pnpm lockfile optional native package entries.
• Accept the new SDK model_not_found error code and refresh Claude model picker story fixtures.

Verification

• pnpm exec turbo run typecheck --filter=@bb/agent-runtime --filter=@bb/app
• pnpm exec turbo run test --filter=@bb/agent-runtime

Notes

• Verified claude-sonnet-5 from the latest official @anthropic-ai/claude-agent-sdk package source and Anthropic Platform model references before coding.