chore: update React and TypeScript dependencies

[kalvinnchau]

Technical changes

• Updates streamdown from 2.5.0 to 2.6.0.
• Advances non-breaking React ecosystem and TypeScript toolchain dependencies within their existing major-version constraints.
• Compares shared dependency declarations with the squareup/berd-internal overlay and retains the highest declared versions.
• Synchronizes tsx and Node type declarations across the root and vendored SDK workspaces.
• Regenerates pnpm-lock.yaml with pnpm 10.33.0.

Validation

• just check
• just test (7,163 passed; 1 skipped)
• pnpm typecheck
• git diff --check

[morgmart]

🤖 Automated code review

APPROVE. Fresh static review of the exact three-dot comparison e874465...f6b29ec found no publishable issues. The PR only updates dependency declarations and the synchronized pnpm lockfile. Final self-check covered all changed user flows (none directly changed), accessibility, localization, navigation and consent guards, async/error/never-completes/lifecycle/race behavior, test honesty, design-system and project laws, duplicate overlap, and concrete evidence/user effect for severity; no supported finding remained. Supplied GitHub evidence was inspected: all reported substantive checks for the exact head SHA succeeded, with the close job skipped; the legacy combined commit status is pending with no statuses. Required checks still independently govern merge readiness.

Deterministic publication result: 0 blocking and 0 non-blocking finding(s) publishable; 0 duplicate(s) suppressed.

Pending checks: 1 check(s) are not complete.

This approval reflects the completed code review only; merge readiness remains governed by the repository's required checks.